From cea8745cfadb698774cb7b4f930c6f10b7cbdf3c Mon Sep 17 00:00:00 2001
From: Ariver <shanghai3168@gmail.com>
Date: Mon, 29 Jun 2026 01:06:25 +0800
Subject: [PATCH] docs: clarify Aligner2 acceptance QA evidence

---
 C1.source/Sources/Aligner/QuickSwitchRootView.swift | 5018 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 4,611 insertions(+), 407 deletions(-)

diff --git a/C1.source/Sources/Aligner/QuickSwitchRootView.swift b/C1.source/Sources/Aligner/QuickSwitchRootView.swift
index 7c3bd30..7bb50aa 100644
--- a/C1.source/Sources/Aligner/QuickSwitchRootView.swift
+++ b/C1.source/Sources/Aligner/QuickSwitchRootView.swift
@@ -10,9 +10,25 @@
 
 @MainActor
 final class QuickSwitchRootView: NSView {
+    private static let appShelfIndexSymbols = Array("1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ").map(String.init)
+    private static let windowIndexKeyPendingInterval: CFTimeInterval = 0.8
+    private static let appShelfIndexKeyCodes: [String: UInt16] = [
+        "1": 18, "2": 19, "3": 20, "4": 21, "5": 23,
+        "6": 22, "7": 26, "8": 28, "9": 25, "0": 29,
+        "A": 0, "B": 11, "C": 8, "D": 2, "E": 14, "F": 3,
+        "G": 5, "H": 4, "I": 34, "J": 38, "K": 40, "L": 37,
+        "M": 46, "N": 45, "O": 31, "P": 35, "Q": 12, "R": 15,
+        "S": 1, "T": 17, "U": 32, "V": 9, "W": 13, "X": 7,
+        "Y": 16, "Z": 6
+    ]
+
     private let backdropBlurView = NSVisualEffectView()
     private let layerHostView = NSView()
     private let backgroundLayer = CAGradientLayer()
+    private let darkAmbientLeftLayer = CAGradientLayer()
+    private let darkAmbientCenterLayer = CAGradientLayer()
+    private let darkAmbientRightLayer = CAGradientLayer()
+    private let darkVignetteLayer = CAGradientLayer()
     private let safeAreaFillLayer = CALayer()
     private let glassLayer = CALayer()
     private let laneLayer = CALayer()
@@ -22,11 +38,18 @@
     private let waterfallLayer = CALayer()
     private let waterfallContentLayer = CALayer()
     private lazy var closeConfirmationLayers = makeCloseConfirmationLayers()
+    private let closeFeedbackLayer = CALayer()
+    private let closeFeedbackTextLayer = CATextLayer()
+    private let viewModeToggleButtonLayer = CALayer()
+    private let viewModeToggleIconLayer = CALayer()
+    private let themeToggleButtonLayer = CALayer()
+    private let themeToggleIconLayer = CALayer()
     private let appIconProvider: any AppIconProviderProtocol = WorkspaceAppIconProvider()
     private let skeletonThumbnailProvider = NativeSkeletonThumbnailProvider(size: NSSize(width: 160, height: 96))
     private var screenshotSourcesByWindowID: [UInt32: ScreenshotResolutionSource] = [:]
     private var screenshotSkippedReasonsByWindowID: [UInt32: String] = [:]
     private var currentViewModel: QuickSwitchViewModel?
+    private var spaceLaneDisplayGroups: [SpaceLaneDisplayGroupLayers] = []
     private var spaceLaneSegments: [SpaceLaneSegmentLayers] = []
     private var spaceLaneContentWidth: CGFloat = 0
     private var spaceLaneScrollOffset: CGFloat = 0
@@ -35,25 +58,54 @@
     private var appShelfContentWidth: CGFloat = 0
     private var appShelfScrollOffset: CGFloat = 0
     private var appShelfTrackingArea: NSTrackingArea?
+    private var lastKnownMouseWindowLocation: CGPoint?
     private var hoveredAppGroupIndex: Int?
     private var hoveredWindowID: UInt32?
     private var hoveredSpaceID: UInt64?
     private var hoveredCloseTarget: CloseTarget?
     private var pendingCloseTarget: CloseTarget?
+    private var pendingCloseRequest: QuickSwitchCloseRequest?
     private var pendingCloseOptOut = false
     private var closeConfirmationArrowEdge: CloseConfirmationArrowEdge?
     private var closeConfirmationRequired = true
+    private var closeFeedback: CloseFeedback?
+    private var closeFeedbackHideTask: Task<Void, Never>?
+    private var isViewModeToggleButtonHovered = false
+    private var suppressViewModeToggleHoverPreview = false
+    private var isThemeToggleButtonHovered = false
+    private var suppressThemeToggleHoverPreview = false
+    private var hoverTarget: HoverTarget = .none
+    private var hoverTargetSource: HoverTargetSource = .event
     private var hoveredSpaceLaneID: UInt64?
     private var focusedSpaceID: UInt64?
     private var debugHoveredAppGroupIndex: Int?
     private var waterfallColumns: [WaterfallColumnLayers] = []
+    private var waterfallViewMode: QuickSwitchWaterfallViewMode = .verticalColumns
+    private var themePreference: ThemePreference = .light
     private var waterfallContentWidth: CGFloat = 0
     private var waterfallScrollOffset: CGFloat = 0
     private var waterfallColumnScrollOffsets: [Int: CGFloat] = [:]
+    private var horizontalMasonryContentHeight: CGFloat = 0
+    private var horizontalMasonryScrollOffset: CGFloat = 0
     private var currentSelection: QuickSwitchSelection?
     private var columnSelectionHistory: [Int: Int] = [:]
+    private var keyboardFocusedAppGroupIndex: Int?
+    private var keyboardFocusedWindowID: UInt32?
     private var keyboardCommandsApplied: [String] = []
     private var lastKeyboardCommand: String?
+    private var lastKeyboardAppIndexCommand: String?
+    private var appShelfIndexKeyDownCount = 0
+    private var lastAppShelfIndexKeySymbol: String?
+    private var windowIndexKeyPending: WindowIndexKeyPending?
+    private var windowIndexKeyPendingClearTask: Task<Void, Never>?
+    private var lastWindowIndexKeyCommand: String?
+    private var lastWindowIndexKeyCommitCode: String?
+    private var windowShortcutFilterPhase: WindowShortcutFilterPhase = .none
+    private var lastWindowShortcutPreCommitFilterSnapshot: WindowShortcutPreCommitFilterSnapshot?
+    private var lastBoundaryBounceAxis: String?
+    private var lastBoundaryBounceDirection: String?
+    private var boundaryBounceCount = 0
+    private var selectionChangedByLastCommand: Bool?
     private var tabIgnoredCount = 0
     private var lastCommittedSelection: QuickSwitchSelection?
     private var lastCommitSource: QuickSwitchCommitSource?
@@ -70,8 +122,18 @@
     private var keyboardResponseLatencyMilliseconds: [Double] = []
     private var mouseResponseLatencyMilliseconds: [Double] = []
     private var hoverResponseLatencyMilliseconds: [Double] = []
+    private var lastProjectionTransitionMovedLayerCount = 0
+    private var lastProjectionTransitionFadeInLayerCount = 0
+    private var lastProjectionTransitionFadeOutLayerCount = 0
+    private var lastProjectionTransitionDurationMilliseconds: Double = 0
+    private var suppressEventInput = false
+    private var suppressEventBackgroundClicks = false
     var onEscape: (() -> Void)?
     var onCommitSelection: ((QuickSwitchSelection, QuickSwitchCommitSource) -> Void)?
+    var onSpaceLaneClick: ((UInt64, Int) -> Void)?
+    var onBackgroundClick: (() -> Bool)?
+    var onToggleWaterfallViewMode: (() -> Void)?
+    var onToggleTheme: (() -> Void)?
     var onRequestClose: ((QuickSwitchCloseRequest) -> Void)?
     var onCloseConfirmationDisabled: (() -> Void)?
 
@@ -108,9 +170,119 @@
         let cancelButtonTextLayer: CATextLayer
     }
 
+    private struct CloseFeedback: Equatable, Sendable {
+        enum Kind: String, Sendable {
+            case progress
+            case failure
+        }
+
+        let kind: Kind
+        let message: String
+        let targetKind: String
+        let appGroupIndex: Int
+        let windowID: UInt32?
+    }
+
     private enum CloseConfirmationArrowEdge: String {
         case left
         case right
+    }
+
+    private enum HoverTarget: Equatable {
+        case none
+        case space(UInt64)
+        case app(Int)
+        case window(appGroupIndex: Int, windowID: UInt32, spaceID: UInt64?)
+
+        var kindDescription: String {
+            switch self {
+            case .none:
+                return "none"
+            case .space:
+                return "space"
+            case .app:
+                return "app"
+            case .window:
+                return "window"
+            }
+        }
+
+        var appGroupIndex: Int? {
+            switch self {
+            case .app(let appGroupIndex):
+                return appGroupIndex
+            case .window(let appGroupIndex, _, _):
+                return appGroupIndex
+            case .none, .space:
+                return nil
+            }
+        }
+
+        var windowID: UInt32? {
+            switch self {
+            case .window(_, let windowID, _):
+                return windowID
+            case .none, .space, .app:
+                return nil
+            }
+        }
+
+        var spaceID: UInt64? {
+            switch self {
+            case .space(let spaceID):
+                return spaceID
+            case .window(_, _, let spaceID):
+                return spaceID
+            case .none, .app:
+                return nil
+            }
+        }
+
+        var spaceLaneID: UInt64? {
+            guard case .space(let spaceID) = self else { return nil }
+            return spaceID
+        }
+
+        var shouldAlignWaterfallWithAppShelf: Bool {
+            switch self {
+            case .app:
+                return true
+            case .none, .space, .window:
+                return false
+            }
+        }
+    }
+
+    private enum HoverTargetSource: String {
+        case event
+        case debug
+        case keyboard
+    }
+
+    private enum HorizontalKeyboardFocusKind: String {
+        case app
+        case window
+    }
+
+    private struct HorizontalKeyboardFocusNode {
+        let kind: HorizontalKeyboardFocusKind
+        let appGroupIndex: Int
+        let windowIndex: Int?
+        let windowID: UInt32?
+        let spaceID: UInt64?
+        let frame: CGRect
+        let order: Int
+
+        var center: CGPoint {
+            CGPoint(x: frame.midX, y: frame.midY)
+        }
+
+        func matches(_ other: HorizontalKeyboardFocusNode) -> Bool {
+            kind == other.kind
+                && appGroupIndex == other.appGroupIndex
+                && windowIndex == other.windowIndex
+                && windowID == other.windowID
+        }
     }
 
     private struct SpaceLaneSegmentLayers {
@@ -119,14 +291,22 @@
         let labelLayer: CATextLayer
         let countLayer: CATextLayer
         let appLayer: CATextLayer
+        let splitAppLayers: [CATextLayer]
         let windowBlocks: [CALayer]
         let fullscreenMarkerLayer: CALayer?
+    }
+
+    private struct SpaceLaneDisplayGroupLayers {
+        let display: QuickSwitchDisplayViewModel
+        let containerLayer: CALayer
+        let segments: [SpaceLaneSegmentLayers]
     }
 
     private struct AppShelfItemLayers {
         let item: QuickSwitchAppShelfItemViewModel
         let containerLayer: CALayer
         let backgroundLayer: CALayer
+        let indexLayer: CATextLayer
         let iconLayer: CALayer
         let labelLayer: CATextLayer
         let badgeLayer: CATextLayer
@@ -142,6 +322,7 @@
     private struct WaterfallColumnLayers {
         let column: QuickSwitchWaterfallColumnViewModel
         let containerLayer: CALayer
+        let cardsClipLayer: CALayer
         let headerLayer: CALayer
         let appNameLayer: CATextLayer
         let countLayer: CATextLayer
@@ -161,6 +342,69 @@
         let closeButton: CloseButtonLayers
     }
 
+    private struct WindowIndexKeyPending {
+        let appSymbol: String
+        let appGroupIndex: Int
+        let startedAt: CFTimeInterval
+    }
+
+    private enum WindowShortcutFilterPhase: String {
+        case none
+        case appPending
+        case targetPreCommit
+        case invalid
+        case expired
+    }
+
+    private enum WindowShortcutFilterState: String {
+        case none
+        case matched
+        case dimmed
+        case target
+    }
+
+    private struct WindowShortcutPreCommitFilterSnapshot {
+        let targetCode: String
+        let targetWindowID: UInt32
+        let matchedWindowIDs: [UInt32]
+        let dimmedWindowIDs: [UInt32]
+
+        var reportDictionary: [String: Any] {
+            [
+                "phase": WindowShortcutFilterPhase.targetPreCommit.rawValue,
+                "targetCode": targetCode,
+                "targetWindowID": Int(targetWindowID),
+                "matchedWindowIDs": matchedWindowIDs.map(Int.init),
+                "dimmedWindowIDs": dimmedWindowIDs.map(Int.init)
+            ]
+        }
+    }
+
+    private struct WindowShortcutFilterReport {
+        let active: Bool
+        let phase: WindowShortcutFilterPhase
+        let pendingAppGroupIndex: Int?
+        let prefix: String?
+        let matchedWindowIDs: [UInt32]
+        let dimmedWindowIDs: [UInt32]
+    }
+
+    private struct ProjectionLayerSnapshot {
+        let layer: CALayer
+        let frame: CGRect
+    }
+
+    private struct ProjectionColumnSnapshot {
+        let layer: CALayer
+        let frame: CGRect
+        let cardsByWindowID: [UInt32: ProjectionLayerSnapshot]
+    }
+
+    private struct ProjectionTransitionSnapshot {
+        let appShelfItemsByAppGroupIndex: [Int: ProjectionLayerSnapshot]
+        let waterfallColumnsByAppGroupIndex: [Int: ProjectionColumnSnapshot]
+    }
+
     private enum AppShelfMetrics {
         static let normalIconSize: CGFloat = 56
         static let hoverIconSize: CGFloat = 68
@@ -169,6 +413,31 @@
         static let normalGap: CGFloat = 16
         static let minGap: CGFloat = 8
         static let maxRows = 2
+        static let indexFontSize: CGFloat = 16
+        static let compressedIndexFontSize: CGFloat = 14
+        static let indexWidth: CGFloat = 18
+        static let indexHeight: CGFloat = 24
+        static let magneticFirstNeighborInfluence: CGFloat = 0
+        static let magneticSecondNeighborInfluence: CGFloat = 0
+        static let magneticHoverLift: CGFloat = 4
+        static let magneticFirstNeighborLift: CGFloat = 0
+        static let magneticSecondNeighborLift: CGFloat = 0
+        static let magneticAnimationDuration: CFTimeInterval = 0.16
+        static let magneticAnimationTimingName = CAMediaTimingFunctionName.easeOut
+        static let closeButtonHitOutset: CGFloat = 0
+    }
+
+    private struct AppShelfMagneticState {
+        let influence: CGFloat
+        let lift: CGFloat
+
+        var isActive: Bool {
+            influence > 0
+        }
+
+        var isNeighbor: Bool {
+            influence > 0 && influence < 1
+        }
     }
 
     private enum RootLayoutMetrics {
@@ -179,16 +448,162 @@
         static let bottomMargin: CGFloat = 34
     }
 
+    private enum ViewModeToggleMetrics {
+        static let hitSize: CGFloat = 34
+        static let visualSize: CGFloat = 30
+        static let cornerRadius: CGFloat = 9
+        static let iconInset: CGFloat = 7
+        static let glyphLineWidth: CGFloat = 1.65
+        static let glyphCornerRadius: CGFloat = 2.1
+        static let selectedShadowRadius: CGFloat = 10
+        static let idleShadowRadius: CGFloat = 5
+    }
+
+    private enum ViewModeToggleVisualState: String {
+        case horizontalAvailable = "H1"
+        case horizontalSelected = "H2"
+        case verticalAvailable = "Z1"
+        case verticalSelected = "Z2"
+    }
+
+    private enum ThemeToggleMetrics {
+        static let buttonGap: CGFloat = 10
+    }
+
+    private enum QuickSwitchResolvedTheme: String {
+        case light
+        case dark
+    }
+
+    private struct QuickSwitchThemePalette {
+        let resolvedTheme: QuickSwitchResolvedTheme
+        let backgroundGradientColors: [NSColor]
+        let safeAreaFill: NSColor
+        let displayGroupBackground: NSColor
+        let spaceLanePrimaryText: NSColor
+        let spaceLaneSecondaryText: NSColor
+        let columnBackground: NSColor
+        let columnBorder: NSColor
+        let columnHeaderBackground: NSColor
+        let columnHeaderHoverBackground: NSColor
+        let columnHeaderSpaceFocusedBackground: NSColor
+        let columnText: NSColor
+        let columnSecondaryText: NSColor
+        let cardBackground: NSColor
+        let cardSelectedBackground: NSColor
+        let cardText: NSColor
+        let cardSecondaryText: NSColor
+        let appShelfLabelText: NSColor
+        let appShelfIndexText: NSColor
+        let appShelfIndexHighlightedText: NSColor
+        let appShelfBackgroundSelected: NSColor
+        let appShelfBackgroundHovered: NSColor
+        let appShelfBackgroundSpaceFocused: NSColor
+        let closeFeedbackBackground: NSColor
+        let closeFeedbackBorder: NSColor
+        let closeFeedbackText: NSColor
+        let shinePeak: NSColor
+
+        static func palette(for theme: QuickSwitchResolvedTheme) -> QuickSwitchThemePalette {
+            switch theme {
+            case .light:
+                return QuickSwitchThemePalette(
+                    resolvedTheme: .light,
+                    backgroundGradientColors: [
+                        NSColor.windowBackgroundColor.withAlphaComponent(0.58),
+                        NSColor.controlBackgroundColor.withAlphaComponent(0.48)
+                    ],
+                    safeAreaFill: .black,
+                    displayGroupBackground: NSColor.windowBackgroundColor,
+                    spaceLanePrimaryText: .labelColor,
+                    spaceLaneSecondaryText: .secondaryLabelColor,
+                    columnBackground: NSColor.controlBackgroundColor.withAlphaComponent(0.56),
+                    columnBorder: NSColor.separatorColor.withAlphaComponent(0.24),
+                    columnHeaderBackground: NSColor.controlBackgroundColor.withAlphaComponent(0.52),
+                    columnHeaderHoverBackground: NSColor.systemGray.withAlphaComponent(0.22),
+                    columnHeaderSpaceFocusedBackground: NSColor.systemFill.withAlphaComponent(0.10),
+                    columnText: .labelColor,
+                    columnSecondaryText: .secondaryLabelColor,
+                    cardBackground: NSColor.windowBackgroundColor.withAlphaComponent(0.82),
+                    cardSelectedBackground: NSColor.windowBackgroundColor.withAlphaComponent(0.94),
+                    cardText: .labelColor,
+                    cardSecondaryText: .secondaryLabelColor,
+                    appShelfLabelText: .secondaryLabelColor,
+                    appShelfIndexText: NSColor.labelColor.withAlphaComponent(0.48),
+                    appShelfIndexHighlightedText: NSColor.labelColor.withAlphaComponent(0.58),
+                    appShelfBackgroundSelected: NSColor.controlAccentColor.withAlphaComponent(0.14),
+                    appShelfBackgroundHovered: NSColor.controlAccentColor.withAlphaComponent(0.13),
+                    appShelfBackgroundSpaceFocused: NSColor.controlAccentColor.withAlphaComponent(0.14),
+                    closeFeedbackBackground: NSColor.windowBackgroundColor.withAlphaComponent(0.94),
+                    closeFeedbackBorder: NSColor.separatorColor.withAlphaComponent(0.28),
+                    closeFeedbackText: NSColor.secondaryLabelColor.withAlphaComponent(0.96),
+                    shinePeak: NSColor.white.withAlphaComponent(0.16)
+                )
+            case .dark:
+                return QuickSwitchThemePalette(
+                    resolvedTheme: .dark,
+                    backgroundGradientColors: [
+                        NSColor(calibratedRed: 5 / 255, green: 8 / 255, blue: 20 / 255, alpha: 1),
+                        NSColor(calibratedRed: 15 / 255, green: 24 / 255, blue: 54 / 255, alpha: 1),
+                        NSColor(calibratedRed: 3 / 255, green: 42 / 255, blue: 52 / 255, alpha: 1),
+                        NSColor(calibratedRed: 2 / 255, green: 6 / 255, blue: 13 / 255, alpha: 1)
+                    ],
+                    safeAreaFill: .black,
+                    displayGroupBackground: NSColor(calibratedRed: 14 / 255, green: 24 / 255, blue: 39 / 255, alpha: 0.72),
+                    spaceLanePrimaryText: NSColor.white.withAlphaComponent(0.88),
+                    spaceLaneSecondaryText: NSColor.white.withAlphaComponent(0.56),
+                    columnBackground: NSColor(calibratedRed: 92 / 255, green: 97 / 255, blue: 111 / 255, alpha: 0.72),
+                    columnBorder: NSColor.white.withAlphaComponent(0.20),
+                    columnHeaderBackground: NSColor(calibratedRed: 104 / 255, green: 111 / 255, blue: 126 / 255, alpha: 0.70),
+                    columnHeaderHoverBackground: NSColor(calibratedRed: 185 / 255, green: 190 / 255, blue: 205 / 255, alpha: 0.32),
+                    columnHeaderSpaceFocusedBackground: NSColor(calibratedRed: 92 / 255, green: 171 / 255, blue: 255 / 255, alpha: 0.16),
+                    columnText: NSColor.black.withAlphaComponent(0.82),
+                    columnSecondaryText: NSColor.black.withAlphaComponent(0.46),
+                    cardBackground: NSColor.white.withAlphaComponent(0.90),
+                    cardSelectedBackground: NSColor.white.withAlphaComponent(0.96),
+                    cardText: NSColor.black.withAlphaComponent(0.86),
+                    cardSecondaryText: NSColor.black.withAlphaComponent(0.52),
+                    appShelfLabelText: NSColor.white.withAlphaComponent(0.66),
+                    appShelfIndexText: NSColor.white.withAlphaComponent(0.40),
+                    appShelfIndexHighlightedText: NSColor.white.withAlphaComponent(0.58),
+                    appShelfBackgroundSelected: NSColor(calibratedRed: 92 / 255, green: 171 / 255, blue: 255 / 255, alpha: 0.22),
+                    appShelfBackgroundHovered: NSColor(calibratedRed: 92 / 255, green: 171 / 255, blue: 255 / 255, alpha: 0.18),
+                    appShelfBackgroundSpaceFocused: NSColor(calibratedRed: 92 / 255, green: 171 / 255, blue: 255 / 255, alpha: 0.20),
+                    closeFeedbackBackground: NSColor(calibratedRed: 36 / 255, green: 43 / 255, blue: 58 / 255, alpha: 0.96),
+                    closeFeedbackBorder: NSColor.white.withAlphaComponent(0.18),
+                    closeFeedbackText: NSColor.white.withAlphaComponent(0.76),
+                    shinePeak: NSColor.white.withAlphaComponent(0.10)
+                )
+            }
+        }
+    }
+
     private enum WaterfallMetrics {
         static let gap: CGFloat = 16
         static let columnWidth: CGFloat = 252
         static let columnMinWidth: CGFloat = 220
         static let columnMaxWidth: CGFloat = 292
-        static let columnPadding: CGFloat = 12
+        static let contentHorizontalPadding: CGFloat = 0
+        static let columnHorizontalPadding: CGFloat = 0
+        static let columnVerticalPadding: CGFloat = 0
+        static let columnHeaderTextInset: CGFloat = 12
         static let headerHeight: CGFloat = 34
         static let cardHeight: CGFloat = 138
         static let cardGap: CGFloat = 12
         static let revealPadding: CGFloat = 24
+        static let horizontalRevealPadding: CGFloat = 0
+        static let selectedCardScale: CGFloat = 1.015
+        static let selectedCardScaleOverflow: CGFloat = cardHeight * (selectedCardScale - 1) / 2
+    }
+
+    private enum HorizontalMasonryMetrics {
+        static let horizontalPadding: CGFloat = 12
+        static let verticalPadding: CGFloat = 0
+        static let horizontalGap: CGFloat = 16
+        static let verticalGap: CGFloat = WaterfallMetrics.cardGap
+        static let cardMinWidth: CGFloat = 220
+        static let cardMaxWidth: CGFloat = 320
+        static let cardHeight: CGFloat = WaterfallMetrics.cardHeight
     }
 
     private enum WaterfallHorizontalIntent {
@@ -200,6 +615,16 @@
         static let tolerance: CGFloat = 1
         static let animationDuration: CFTimeInterval = 0.18
         static let animationTimingName = CAMediaTimingFunctionName.easeOut
+    }
+
+    private enum SpaceLaneMetrics {
+        static let horizontalPadding: CGFloat = 0
+        static let groupGap: CGFloat = 36
+        static let groupHorizontalPadding: CGFloat = 24
+        static let groupVerticalPadding: CGFloat = 6
+        static let segmentGap: CGFloat = 12
+        static let segmentMinWidth: CGFloat = 96
+        static let segmentMaxWidth: CGFloat = 150
     }
 
     override init(frame frameRect: NSRect) {
@@ -231,7 +656,7 @@
 
         let trackingArea = NSTrackingArea(
             rect: bounds,
-            options: [.activeInKeyWindow, .mouseMoved, .mouseEnteredAndExited, .inVisibleRect],
+            options: [.activeAlways, .mouseMoved, .mouseEnteredAndExited, .inVisibleRect],
             owner: self,
             userInfo: nil
         )
@@ -247,6 +672,13 @@
     }
 
     override func keyDown(with event: NSEvent) {
+        if suppressEventInput {
+            DevelopmentDiagnostics.log("quickSwitch.view.keyDown.ignoredForDebugSequence", [
+                "keyCode": event.keyCode
+            ])
+            return
+        }
+
         switch event.keyCode {
         case TriggerKeyCode.escape where Self.shouldDismissOnEscape(event):
             onEscape?()
@@ -263,11 +695,17 @@
         case TriggerKeyCode.tab:
             performKeyboardCommand("tab")
         default:
+            if handleAppShelfIndexKey(event) {
+                return
+            }
             super.keyDown(with: event)
         }
     }
 
     override func scrollWheel(with event: NSEvent) {
+        clearWindowIndexKeyPending()
+        refreshHoverTarget(at: event.locationInWindow)
+
         let dominantDelta = abs(event.scrollingDeltaX) >= abs(event.scrollingDeltaY)
             ? event.scrollingDeltaX
             : event.scrollingDeltaY
@@ -287,6 +725,15 @@
         }
 
         if shouldScrollWaterfall(for: event) {
+            if isHorizontalMasonryMode {
+                let currentOffset = horizontalMasonryScrollOffset
+                horizontalMasonryScrollOffset = clampedHorizontalMasonryOffset(
+                    currentOffset - event.scrollingDeltaY
+                )
+                needsLayout = true
+                return
+            }
+
             if abs(event.scrollingDeltaX) >= abs(event.scrollingDeltaY), waterfallAlignmentScrollable {
                 waterfallScrollOffset = clampedWaterfallAlignmentOffset(waterfallScrollOffset - event.scrollingDeltaX)
                 needsLayout = true
@@ -312,90 +759,137 @@
 
     override func mouseMoved(with event: NSEvent) {
         guard debugHoveredAppGroupIndex == nil else { return }
+        lastKnownMouseWindowLocation = event.locationInWindow
+        clearWindowIndexKeyPending()
+
+        let toggleHovered = viewModeToggleButtonContains(windowLocation: event.locationInWindow)
+        let themeHovered = themeToggleButtonContains(windowLocation: event.locationInWindow)
+        if !toggleHovered {
+            suppressViewModeToggleHoverPreview = false
+        }
+        if !themeHovered {
+            suppressThemeToggleHoverPreview = false
+        }
+        let shouldShowToggleHoverPreview = toggleHovered && !suppressViewModeToggleHoverPreview
+        if isViewModeToggleButtonHovered != shouldShowToggleHoverPreview {
+            isViewModeToggleButtonHovered = shouldShowToggleHoverPreview
+            needsLayout = true
+        }
+        let shouldShowThemeHoverPreview = themeHovered && !suppressThemeToggleHoverPreview
+        if isThemeToggleButtonHovered != shouldShowThemeHoverPreview {
+            isThemeToggleButtonHovered = shouldShowThemeHoverPreview
+            needsLayout = true
+        }
+        if toggleHovered || themeHovered {
+            hoveredCloseTarget = nil
+            setHoverTarget(.none)
+            return
+        }
 
         let closeTarget = closeButtonTarget(at: event.locationInWindow)
         if hoveredCloseTarget != closeTarget {
             hoveredCloseTarget = closeTarget
             needsLayout = true
         }
-
-        if let segment = spaceLaneSegment(at: event.locationInWindow) {
-            hoverSpaceLaneSegment(segment)
-            return
-        }
-
-        if let card = waterfallCard(at: event.locationInWindow) {
-            hoveredSpaceLaneID = nil
-            updateHoverState(
-                appGroupIndex: card.item.appGroupIndex,
-                windowID: card.item.window.id,
-                spaceID: card.item.primarySpaceID
-            )
-            return
-        }
-
-        if let item = appShelfItem(at: event.locationInWindow) {
-            hoveredSpaceLaneID = nil
-            updateHoverState(
-                appGroupIndex: item.item.appGroupIndex,
-                windowID: nil,
-                spaceID: nil,
-                alignsWaterfallWithAppShelf: true
-            )
-            return
-        }
-
-        hoveredSpaceLaneID = nil
-        hoveredCloseTarget = nil
-        updateHoverState(appGroupIndex: nil, windowID: nil, spaceID: nil)
+        refreshHoverTarget(at: event.locationInWindow)
     }
 
     override func mouseExited(with event: NSEvent) {
         guard debugHoveredAppGroupIndex == nil else { return }
-        hoveredSpaceLaneID = nil
+        lastKnownMouseWindowLocation = nil
+        clearWindowIndexKeyPending()
+        isViewModeToggleButtonHovered = false
+        suppressViewModeToggleHoverPreview = false
+        isThemeToggleButtonHovered = false
+        suppressThemeToggleHoverPreview = false
         hoveredCloseTarget = nil
-        updateHoverState(appGroupIndex: nil, windowID: nil, spaceID: nil)
+        setHoverTarget(.none)
     }
 
     override func mouseDown(with event: NSEvent) {
-        if handleCloseConfirmationMouseDown(at: event.locationInWindow) {
+        if suppressEventInput {
+            DevelopmentDiagnostics.log("quickSwitch.view.mouseDown.ignoredForDebugSequence", [
+                "x": event.locationInWindow.x,
+                "y": event.locationInWindow.y,
+                "bounds": NSStringFromRect(bounds)
+            ])
             return
         }
 
-        if let closeTarget = closeButtonTarget(at: event.locationInWindow) {
+        if handleMouseDown(at: event.locationInWindow, clickCount: max(1, event.clickCount), allowBackgroundClick: true) {
+            return
+        }
+
+        super.mouseDown(with: event)
+    }
+
+    @discardableResult
+    private func handleMouseDown(at windowLocation: CGPoint, clickCount: Int, allowBackgroundClick: Bool) -> Bool {
+        clearWindowIndexKeyPending()
+
+        if handleCloseConfirmationMouseDown(at: windowLocation) {
+            return true
+        }
+
+        if viewModeToggleButtonContains(windowLocation: windowLocation) {
+            clickViewModeToggleButton(source: "mouse")
+            return true
+        }
+
+        if themeToggleButtonContains(windowLocation: windowLocation) {
+            clickThemeToggleButton(source: "mouse")
+            return true
+        }
+
+        if let closeTarget = waterfallCloseButtonTarget(at: windowLocation) {
             beginCloseConfirmation(for: closeTarget)
-            return
+            return true
         }
 
-        if let card = waterfallCard(at: event.locationInWindow) {
+        if let card = waterfallCard(at: windowLocation) {
             clickWindowCard(card)
-            return
+            return true
         }
 
-        if let segment = spaceLaneSegment(at: event.locationInWindow) {
-            clickSpaceLaneSegment(segment)
-            return
+        if let segment = spaceLaneSegment(at: windowLocation) {
+            clickSpaceLaneSegment(segment, clickCount: max(1, clickCount))
+            return true
         }
 
-        if let item = appShelfItem(at: event.locationInWindow) {
+        if let item = appShelfIconItem(at: windowLocation) {
+            if let closeTarget = appShelfCloseButtonTarget(at: windowLocation) {
+                beginCloseConfirmation(for: closeTarget)
+            } else {
+                clickAppShelfItem(item)
+            }
+            return true
+        }
+
+        if let closeTarget = closeButtonTarget(at: windowLocation) {
+            beginCloseConfirmation(for: closeTarget)
+            return true
+        }
+
+        if let item = appShelfItem(at: windowLocation) {
             clickAppShelfItem(item)
-            return
+            return true
         }
 
         DevelopmentDiagnostics.log("quickSwitch.view.mouseDown.miss", [
-            "x": event.locationInWindow.x,
-            "y": event.locationInWindow.y,
+            "x": windowLocation.x,
+            "y": windowLocation.y,
             "bounds": NSStringFromRect(bounds)
         ])
-        super.mouseDown(with: event)
+        if allowBackgroundClick, !suppressEventBackgroundClicks, onBackgroundClick?() == true {
+            return true
+        }
+        return false
     }
 
     func setDebugHoveredAppGroupIndex(_ index: Int?) {
         debugHoveredAppGroupIndex = index
+        setHoverTarget(.none, source: .debug)
         hoveredAppGroupIndex = index
-        hoveredWindowID = nil
-        hoveredSpaceID = nil
-        hoveredSpaceLaneID = nil
         needsLayout = true
     }
 
@@ -405,11 +899,49 @@
         layoutSubtreeIfNeeded()
         for command in commands {
             let measurementStart = CACurrentMediaTime()
-            performKeyboardCommand(command)
+            if !performDebugPhysicalIndexKeyCommand(command) {
+                performKeyboardCommand(command)
+            }
             layoutSubtreeIfNeeded()
             CATransaction.flush()
             keyboardResponseLatencyMilliseconds.append(milliseconds(since: measurementStart))
         }
+    }
+
+    private func performDebugPhysicalIndexKeyCommand(_ rawCommand: String) -> Bool {
+        let command = rawCommand.trimmingCharacters(in: .whitespacesAndNewlines)
+        let uppercased = command.uppercased()
+        let prefixes = ["PHYSICAL-INDEX:", "PHYSICAL-INDEX-", "KEYDOWN:", "KEYDOWN-"]
+        guard let prefix = prefixes.first(where: { uppercased.hasPrefix($0) }) else {
+            return false
+        }
+
+        let symbolStart = command.index(command.startIndex, offsetBy: prefix.count)
+        guard let symbol = appShelfIndexSymbol(fromKeyboardCommand: String(command[symbolStart...])),
+              let keyCode = Self.appShelfIndexKeyCodes[symbol],
+              let event = NSEvent.keyEvent(
+                with: .keyDown,
+                location: .zero,
+                modifierFlags: [.option],
+                timestamp: ProcessInfo.processInfo.systemUptime,
+                windowNumber: window?.windowNumber ?? 0,
+                context: nil,
+                characters: symbol.lowercased(),
+                charactersIgnoringModifiers: symbol.lowercased(),
+                isARepeat: false,
+                keyCode: keyCode
+              )
+        else {
+            recordKeyboardCommand("invalidPhysicalIndex:\(command)")
+            selectionChangedByLastCommand = false
+            return true
+        }
+
+        let previousSuppressEventInput = suppressEventInput
+        suppressEventInput = false
+        keyDown(with: event)
+        suppressEventInput = previousSuppressEventInput
+        return true
     }
 
     func performDebugMouseCommands(_ commands: [String]) {
@@ -430,6 +962,15 @@
                 break
             }
         }
+    }
+
+    func setSuppressEventBackgroundClicks(_ suppressed: Bool) {
+        suppressEventBackgroundClicks = suppressed
+    }
+
+    func setSuppressEventInput(_ suppressed: Bool) {
+        suppressEventInput = suppressed
+        suppressEventBackgroundClicks = suppressed
     }
 
     func beginPerformanceFirstFrameMeasurement() {
@@ -457,10 +998,67 @@
         closeConfirmationRequired = required
         if !required {
             pendingCloseTarget = nil
+            pendingCloseRequest = nil
             pendingCloseOptOut = false
             closeConfirmationLayers.containerLayer.isHidden = true
             closeConfirmationArrowEdge = nil
         }
+        needsLayout = true
+    }
+
+    func setWaterfallViewMode(_ mode: QuickSwitchWaterfallViewMode) {
+        guard waterfallViewMode != mode else { return }
+
+        waterfallViewMode = mode
+        waterfallScrollOffset = 0
+        waterfallColumnScrollOffsets = [:]
+        horizontalMasonryScrollOffset = 0
+        horizontalMasonryContentHeight = 0
+        needsLayout = true
+    }
+
+    func setTheme(_ theme: ThemePreference) {
+        let normalizedTheme = Self.normalizedQuickSwitchTheme(theme)
+        guard themePreference != normalizedTheme else { return }
+
+        themePreference = normalizedTheme
+        applyThemeToBackdrop()
+        needsLayout = true
+    }
+
+    func showCloseProgress(for request: QuickSwitchCloseRequest) {
+        setCloseFeedback(
+            CloseFeedback(
+                kind: .progress,
+                message: "正在关闭...",
+                targetKind: request.kindDescription,
+                appGroupIndex: request.appGroupIndex,
+                windowID: request.windowID
+            ),
+            autoHideAfter: nil
+        )
+    }
+
+    func showCloseFailure(message: String, for request: QuickSwitchCloseRequest) {
+        setCloseFeedback(
+            CloseFeedback(
+                kind: .failure,
+                message: message,
+                targetKind: request.kindDescription,
+                appGroupIndex: request.appGroupIndex,
+                windowID: request.windowID
+            ),
+            autoHideAfter: 2.75
+        )
+    }
+
+    func clearCloseFeedback() {
+        closeFeedbackHideTask?.cancel()
+        closeFeedbackHideTask = nil
+        closeFeedback = nil
+        closeFeedbackLayer.isHidden = true
+        closeFeedbackLayer.opacity = 0
+        closeFeedbackTextLayer.string = ""
         needsLayout = true
     }
 
@@ -471,7 +1069,10 @@
         guard let card = waterfallCardsByWindowID()[windowID] else { return }
         card.thumbnailLayer.contents = resolution.image
         if case .realScreenshot = resolution.source {
-            card.shineLayer.opacity = card.item.window.id == effectiveSelection?.windowID ? 1 : 0
+            let isSelected = card.item.window.id == effectiveSelection?.windowID
+            let isHovered = card.item.window.id == hoveredWindowID
+            let isKeyboardFocused = card.item.window.id == keyboardFocusedWindowID
+            card.shineLayer.opacity = (shouldShowSelectedVisual(isSelected: isSelected, isHovered: isHovered) || isKeyboardFocused) ? 1 : 0
         }
         needsLayout = true
     }
@@ -488,48 +1089,405 @@
         }
     }
 
+    func effectiveSelectionForProjection() -> QuickSwitchSelection? {
+        effectiveSelection
+    }
+
     func apply(viewModel: QuickSwitchViewModel?) {
+        apply(viewModel: viewModel, preservingInteractionState: false, animatedProjection: false)
+    }
+
+    func applyProjected(viewModel: QuickSwitchViewModel?) {
+        apply(viewModel: viewModel, preservingInteractionState: true, animatedProjection: true)
+    }
+
+    func hoverNextAppGroupIndex(cycleForward: Bool = true) -> Bool {
+        guard !appShelfItems.isEmpty else {
+            return false
+        }
+
+        let orderedIndexes = appShelfItems.map(\.item.appGroupIndex)
+        let sortedIndexes = orderedIndexes
+
+        var currentIndexPosition: Int?
+        if let currentHovered = effectiveHoveredAppGroupIndex {
+            currentIndexPosition = sortedIndexes.firstIndex(of: currentHovered)
+        }
+
+        let nextPosition = currentIndexPosition.map { current in
+            if cycleForward {
+                (current + 1) % sortedIndexes.count
+            } else {
+                (current - 1 + sortedIndexes.count) % sortedIndexes.count
+            }
+        } ?? 0
+
+        let nextAppGroupIndex = sortedIndexes[nextPosition]
+        hoverAppGroup(nextAppGroupIndex)
+        return true
+    }
+
+    private func apply(
+        viewModel: QuickSwitchViewModel?,
+        preservingInteractionState: Bool,
+        animatedProjection: Bool
+    ) {
+        let preservedWindowThumbnails = preservingInteractionState ? cachedThumbnailsByWindowID() : [:]
+        let transitionSnapshot = animatedProjection ? captureProjectionTransitionSnapshot() : nil
+        if !animatedProjection {
+            resetProjectionTransitionReport()
+        }
         currentViewModel = viewModel
-        screenshotSourcesByWindowID = [:]
-        screenshotSkippedReasonsByWindowID = [:]
-        currentSelection = viewModel?.initialSelection
-        columnSelectionHistory = [:]
-        keyboardCommandsApplied = []
-        lastKeyboardCommand = nil
-        tabIgnoredCount = 0
-        lastCommittedSelection = nil
-        lastCommitSource = nil
-        mouseCommandsApplied = []
-        lastMouseCommand = nil
-        lastClickedAppGroupIndex = nil
-        lastAppShelfClickChangedSelection = nil
-        lastClickedWindowID = nil
-        lastSpaceFocusedAppGroupIndex = nil
-        lastSpaceLaneClickSpaceID = nil
-        lastAppShelfScrollSyncedAppGroupIndex = nil
-        hoveredWindowID = nil
-        hoveredSpaceID = nil
-        hoveredCloseTarget = nil
-        pendingCloseTarget = nil
-        pendingCloseOptOut = false
-        closeConfirmationLayers.containerLayer.isHidden = true
-        closeConfirmationArrowEdge = nil
-        hoveredSpaceLaneID = nil
-        focusedSpaceID = nil
-        if debugHoveredAppGroupIndex == nil {
-            hoveredAppGroupIndex = nil
+
+        if preservingInteractionState {
+            currentSelection = validSelection(currentSelection, in: viewModel) ?? viewModel?.initialSelection
+            columnSelectionHistory = columnSelectionHistory.filter { appGroupIndex, _ in
+                viewModel?.waterfallColumns.contains { $0.appGroupIndex == appGroupIndex } == true
+            }
+            if let keyboardFocusedAppGroupIndex,
+               viewModel?.waterfallColumns.contains(where: { $0.appGroupIndex == keyboardFocusedAppGroupIndex }) != true {
+                self.keyboardFocusedAppGroupIndex = nil
+            }
+            if let keyboardFocusedWindowID,
+               viewModel?.waterfallColumns.contains(where: { column in
+                   column.windows.contains { $0.window.id == keyboardFocusedWindowID }
+               }) != true {
+                self.keyboardFocusedWindowID = nil
+            }
+            if let currentSelection {
+                columnSelectionHistory[currentSelection.appGroupIndex] = currentSelection.windowIndex
+            }
+            hoveredCloseTarget = nil
+            pendingCloseTarget = nil
+            pendingCloseRequest = nil
+            pendingCloseOptOut = false
+            closeConfirmationLayers.containerLayer.isHidden = true
+            closeConfirmationArrowEdge = nil
         } else {
+            screenshotSourcesByWindowID = [:]
+            screenshotSkippedReasonsByWindowID = [:]
+            currentSelection = viewModel?.initialSelection
+            columnSelectionHistory = [:]
+            keyboardFocusedAppGroupIndex = nil
+            keyboardFocusedWindowID = nil
+            keyboardCommandsApplied = []
+            lastKeyboardCommand = nil
+            lastKeyboardAppIndexCommand = nil
+            appShelfIndexKeyDownCount = 0
+            lastAppShelfIndexKeySymbol = nil
+            clearWindowIndexKeyPending()
+            lastWindowIndexKeyCommand = nil
+            lastWindowIndexKeyCommitCode = nil
+            windowShortcutFilterPhase = .none
+            lastWindowShortcutPreCommitFilterSnapshot = nil
+            lastBoundaryBounceAxis = nil
+            lastBoundaryBounceDirection = nil
+            boundaryBounceCount = 0
+            selectionChangedByLastCommand = nil
+            tabIgnoredCount = 0
+            lastCommittedSelection = nil
+            lastCommitSource = nil
+            mouseCommandsApplied = []
+            lastMouseCommand = nil
+            lastClickedAppGroupIndex = nil
+            lastAppShelfClickChangedSelection = nil
+            lastClickedWindowID = nil
+            lastSpaceFocusedAppGroupIndex = nil
+            lastSpaceLaneClickSpaceID = nil
+            lastAppShelfScrollSyncedAppGroupIndex = nil
+            waterfallScrollOffset = 0
+            waterfallColumnScrollOffsets = [:]
+            horizontalMasonryScrollOffset = 0
+            horizontalMasonryContentHeight = 0
+            focusedSpaceID = nil
+            hoveredCloseTarget = nil
+            pendingCloseTarget = nil
+            pendingCloseRequest = nil
+            pendingCloseOptOut = false
+            closeConfirmationLayers.containerLayer.isHidden = true
+            closeConfirmationArrowEdge = nil
+            clearCloseFeedback()
+            setHoverTarget(.none)
             hoveredAppGroupIndex = debugHoveredAppGroupIndex
         }
+
         if let currentSelection {
             columnSelectionHistory[currentSelection.appGroupIndex] = currentSelection.windowIndex
         }
         rebuildSpaceLaneSegments()
         rebuildAppShelfItems()
         rebuildWaterfallColumns()
+
+        if preservingInteractionState {
+            restoreThumbnailsFromCache(preservedWindowThumbnails)
+        }
+
         needsLayout = true
         ensureCurrentSelectionVisible(horizontalIntent: .alignWithAppShelf(animated: false))
+        refreshHoverTargetAfterViewRebuild()
         needsLayout = true
+        if animatedProjection, let transitionSnapshot {
+            layoutSubtreeIfNeeded()
+            applyProjectionTransitionAnimations(from: transitionSnapshot)
+        }
+    }
+
+    private func cachedThumbnailsByWindowID() -> [UInt32: Any] {
+        var snapshots: [UInt32: Any] = [:]
+
+        for card in waterfallCardsByWindowID().values {
+            snapshots[card.item.window.id] = card.thumbnailLayer.contents
+        }
+
+        return snapshots
+    }
+
+    private func restoreThumbnailsFromCache(_ cachedThumbnails: [UInt32: Any]) {
+        for card in waterfallCardsByWindowID().values {
+            if let thumbnail = cachedThumbnails[card.item.window.id] {
+                card.thumbnailLayer.contents = thumbnail
+            }
+        }
+    }
+
+    private func validSelection(
+        _ selection: QuickSwitchSelection?,
+        in viewModel: QuickSwitchViewModel?
+    ) -> QuickSwitchSelection? {
+        guard let selection, let viewModel else { return nil }
+
+        for column in viewModel.waterfallColumns {
+            if let card = column.windows.first(where: { $0.window.id == selection.windowID }) {
+                return QuickSwitchSelection(
+                    appGroupIndex: card.appGroupIndex,
+                    windowIndex: card.windowIndex,
+                    windowID: card.window.id
+                )
+            }
+        }
+
+        return nil
+    }
+
+    private func captureProjectionTransitionSnapshot() -> ProjectionTransitionSnapshot {
+        ProjectionTransitionSnapshot(
+            appShelfItemsByAppGroupIndex: Dictionary(
+                uniqueKeysWithValues: appShelfItems.map { item in
+                    (
+                        item.item.appGroupIndex,
+                        ProjectionLayerSnapshot(
+                            layer: item.containerLayer,
+                            frame: item.containerLayer.frame
+                        )
+                    )
+                }
+            ),
+            waterfallColumnsByAppGroupIndex: Dictionary(
+                uniqueKeysWithValues: waterfallColumns.map { column in
+                    (
+                        column.column.appGroupIndex,
+                        ProjectionColumnSnapshot(
+                            layer: column.containerLayer,
+                            frame: column.containerLayer.frame,
+                            cardsByWindowID: Dictionary(
+                                uniqueKeysWithValues: column.cards.map { card in
+                                    (
+                                        card.item.window.id,
+                                        ProjectionLayerSnapshot(
+                                            layer: card.containerLayer,
+                                            frame: card.containerLayer.frame
+                                        )
+                                    )
+                                }
+                            )
+                        )
+                    )
+                }
+            )
+        )
+    }
+
+    private func applyProjectionTransitionAnimations(from snapshot: ProjectionTransitionSnapshot) {
+        let reduceMotion = NSWorkspace.shared.accessibilityDisplayShouldReduceMotion
+        let duration: CFTimeInterval = reduceMotion ? 0.12 : 0.21
+        let timing = CAMediaTimingFunction(name: reduceMotion ? .linear : .easeOut)
+        var movedLayerCount = 0
+        var fadeInLayerCount = 0
+        var fadeOutLayerCount = 0
+
+        for item in appShelfItems {
+            guard let oldSnapshot = snapshot.appShelfItemsByAppGroupIndex[item.item.appGroupIndex] else {
+                if addFadeInAnimation(to: item.containerLayer, duration: duration, timing: timing) {
+                    fadeInLayerCount += 1
+                }
+                continue
+            }
+            if addPositionAnimation(to: item.containerLayer, from: oldSnapshot.frame, duration: duration, timing: timing) {
+                movedLayerCount += 1
+            }
+        }
+
+        let visibleAppGroupIndexes = Set(appShelfItems.map(\.item.appGroupIndex))
+        for (appGroupIndex, oldSnapshot) in snapshot.appShelfItemsByAppGroupIndex
+            where !visibleAppGroupIndexes.contains(appGroupIndex) {
+            if addFadeOutSnapshot(
+                oldSnapshot,
+                to: appShelfContentLayer,
+                frame: oldSnapshot.frame,
+                duration: duration,
+                timing: timing
+            ) {
+                fadeOutLayerCount += 1
+            }
+        }
+
+        for column in waterfallColumns {
+            guard let oldSnapshot = snapshot.waterfallColumnsByAppGroupIndex[column.column.appGroupIndex] else {
+                if addFadeInAnimation(to: column.containerLayer, duration: duration, timing: timing) {
+                    fadeInLayerCount += 1
+                }
+                continue
+            }
+            if addPositionAnimation(to: column.containerLayer, from: oldSnapshot.frame, duration: duration, timing: timing) {
+                movedLayerCount += 1
+            }
+
+            for card in column.cards {
+                guard let oldCardSnapshot = oldSnapshot.cardsByWindowID[card.item.window.id] else {
+                    if addFadeInAnimation(to: card.containerLayer, duration: duration, timing: timing) {
+                        fadeInLayerCount += 1
+                    }
+                    continue
+                }
+                if addPositionAnimation(to: card.containerLayer, from: oldCardSnapshot.frame, duration: duration, timing: timing) {
+                    movedLayerCount += 1
+                }
+            }
+        }
+
+        let visibleColumnsByAppGroupIndex = Dictionary(
+            uniqueKeysWithValues: waterfallColumns.map { ($0.column.appGroupIndex, $0) }
+        )
+        for (appGroupIndex, oldSnapshot) in snapshot.waterfallColumnsByAppGroupIndex {
+            guard let visibleColumn = visibleColumnsByAppGroupIndex[appGroupIndex] else {
+                if addFadeOutSnapshot(
+                    ProjectionLayerSnapshot(layer: oldSnapshot.layer, frame: oldSnapshot.frame),
+                    to: waterfallContentLayer,
+                    frame: oldSnapshot.frame,
+                    duration: duration,
+                    timing: timing
+                ) {
+                    fadeOutLayerCount += 1
+                }
+                continue
+            }
+
+            let visibleWindowIDs = Set(visibleColumn.cards.map(\.item.window.id))
+            for (windowID, oldCardSnapshot) in oldSnapshot.cardsByWindowID
+                where !visibleWindowIDs.contains(windowID) {
+                let absoluteFrame = oldCardSnapshot.frame.offsetBy(
+                    dx: oldSnapshot.frame.minX,
+                    dy: oldSnapshot.frame.minY
+                )
+                if addFadeOutSnapshot(
+                    oldCardSnapshot,
+                    to: waterfallContentLayer,
+                    frame: absoluteFrame,
+                    duration: duration,
+                    timing: timing
+                ) {
+                    fadeOutLayerCount += 1
+                }
+            }
+        }
+
+        lastProjectionTransitionMovedLayerCount = movedLayerCount
+        lastProjectionTransitionFadeInLayerCount = fadeInLayerCount
+        lastProjectionTransitionFadeOutLayerCount = fadeOutLayerCount
+        lastProjectionTransitionDurationMilliseconds = duration * 1_000
+    }
+
+    private func resetProjectionTransitionReport() {
+        lastProjectionTransitionMovedLayerCount = 0
+        lastProjectionTransitionFadeInLayerCount = 0
+        lastProjectionTransitionFadeOutLayerCount = 0
+        lastProjectionTransitionDurationMilliseconds = 0
+    }
+
+    @discardableResult
+    private func addPositionAnimation(
+        to layer: CALayer,
+        from oldFrame: CGRect,
+        duration: CFTimeInterval,
+        timing: CAMediaTimingFunction
+    ) -> Bool {
+        let oldPosition = CGPoint(x: oldFrame.midX, y: oldFrame.midY)
+        let newPosition = layer.position
+        guard abs(oldPosition.x - newPosition.x) > 0.5 || abs(oldPosition.y - newPosition.y) > 0.5 else {
+            return false
+        }
+
+        let animation = CABasicAnimation(keyPath: "position")
+        animation.fromValue = oldPosition
+        animation.toValue = newPosition
+        animation.duration = duration
+        animation.timingFunction = timing
+        animation.isRemovedOnCompletion = true
+        layer.add(animation, forKey: "quickSwitchProjectionPosition")
+        return true
+    }
+
+    @discardableResult
+    private func addFadeInAnimation(
+        to layer: CALayer,
+        duration: CFTimeInterval,
+        timing: CAMediaTimingFunction
+    ) -> Bool {
+        let animation = CABasicAnimation(keyPath: "opacity")
+        animation.fromValue = 0
+        animation.toValue = layer.opacity
+        animation.duration = duration
+        animation.timingFunction = timing
+        animation.isRemovedOnCompletion = true
+        layer.add(animation, forKey: "quickSwitchProjectionFadeIn")
+        return true
+    }
+
+    @discardableResult
+    private func addFadeOutSnapshot(
+        _ snapshot: ProjectionLayerSnapshot,
+        to parentLayer: CALayer,
+        frame: CGRect,
+        duration: CFTimeInterval,
+        timing: CAMediaTimingFunction
+    ) -> Bool {
+        let layer = snapshot.layer
+        layer.removeAllAnimations()
+        layer.removeFromSuperlayer()
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        layer.frame = frame
+        layer.opacity = max(layer.opacity, 0.01)
+        layer.zPosition = max(layer.zPosition, 240)
+        parentLayer.addSublayer(layer)
+        CATransaction.commit()
+
+        let animation = CABasicAnimation(keyPath: "opacity")
+        animation.fromValue = layer.opacity
+        animation.toValue = 0
+        animation.duration = duration
+        animation.timingFunction = timing
+        animation.isRemovedOnCompletion = true
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        layer.opacity = 0
+        CATransaction.commit()
+        layer.add(animation, forKey: "quickSwitchProjectionFadeOut")
+
+        DispatchQueue.main.asyncAfter(deadline: .now() + duration + 0.05) { [weak layer] in
+            layer?.removeFromSuperlayer()
+        }
+        return true
     }
 
     func reportDictionary() -> [String: Any] {
@@ -541,6 +1499,7 @@
         let firstFrameGatePassed = firstFrameP95.map { $0 < 150 } ?? false
         let keyboardGatePassed = keyboardP95.map { $0 < 50 } ?? false
         let hoverGatePassed = hoverP95.map { $0 <= 32 } ?? false
+        let shortcutFilterReport = makeWindowShortcutFilterReport()
 
         return [
             "viewClass": String(describing: Self.self),
@@ -553,17 +1512,56 @@
             "glassBorderWidth": Double(glassLayer.borderWidth),
             "glassShadowOpacity": Double(glassLayer.shadowOpacity),
             "spaceLaneFrame": dictionary(from: laneLayer.frame),
+            "spaceLaneBackgroundColor": colorDictionary(from: laneLayer.backgroundColor),
+            "spaceLaneCornerRadius": Double(laneLayer.cornerRadius),
             "spaceLaneContentWidth": Double(spaceLaneContentWidth),
             "spaceLaneVisibleWidth": Double(laneLayer.bounds.width),
             "spaceLaneMaxScrollOffset": Double(spaceLaneMaxScrollOffset),
             "spaceLaneScrollable": spaceLaneMaxScrollOffset > 0,
+            "spaceLaneDisplayGroupCount": spaceLaneDisplayGroups.count,
+            "spaceLaneDisplayGroups": spaceLaneDisplayGroupReports(),
             "spaceLaneSegmentCount": spaceLaneSegments.count,
             "spaceLaneLabels": currentViewModel?.displays.flatMap { $0.spaces.map(\.label) } ?? [],
             "spaceLaneSegments": spaceLaneSegmentReports(),
+            "hoverTargetKind": hoverTarget.kindDescription,
+            "hoverTargetSource": hoverTargetSource.rawValue,
             "spaceLaneHoveredSpaceID": hoveredSpaceLaneID ?? NSNull(),
             "spaceLaneFocusedSpaceID": focusedSpaceID ?? NSNull(),
             "activeSpaceFocusID": activeSpaceFocusID ?? NSNull(),
+            "spaceFilterLockedSpaceID": currentViewModel?.lockedSpaceID ?? NSNull(),
+            "spaceFilterActive": currentViewModel?.lockedSpaceID != nil,
+            "viewModeToggleButtonVisible": !viewModeToggleButtonLayer.isHidden,
+            "viewModeToggleButtonHovered": isViewModeToggleButtonHovered,
+            "viewModeToggleHoverPreviewSuppressed": suppressViewModeToggleHoverPreview,
+            "viewModeToggleButtonFrame": dictionary(from: viewModeToggleButtonLayer.frame),
+            "viewModeToggleHitSize": Double(ViewModeToggleMetrics.hitSize),
+            "viewModeToggleVisualSize": Double(ViewModeToggleMetrics.visualSize),
+            "viewModeToggleCurrentMode": waterfallViewMode.rawValue,
+            "viewModeToggleTargetMode": nextWaterfallViewMode.rawValue,
+            "viewModeToggleIconKind": viewModeToggleIconKind,
+            "viewModeToggleVisualState": viewModeToggleVisualState.rawValue,
+            "viewModeToggleStandardBlueColor": colorDictionary(from: viewModeToggleBlueColor.cgColor),
+            "viewModeToggleGlyphLineWidth": Double(ViewModeToggleMetrics.glyphLineWidth),
+            "viewModeToggleAccessibilityLabel": viewModeToggleAccessibilityLabel,
+            "themeCurrentPreference": themePreference.rawValue,
+            "themeResolved": resolvedTheme.rawValue,
+            "themeNextPreference": nextThemePreference.rawValue,
+            "themeToggleButtonVisible": !themeToggleButtonLayer.isHidden,
+            "themeToggleButtonHovered": isThemeToggleButtonHovered,
+            "themeToggleHoverPreviewSuppressed": suppressThemeToggleHoverPreview,
+            "themeToggleButtonFrame": dictionary(from: themeToggleButtonLayer.frame),
+            "themeToggleHitSize": Double(ViewModeToggleMetrics.hitSize),
+            "themeToggleVisualSize": Double(ViewModeToggleMetrics.visualSize),
+            "themeToggleIconKind": "halfDisk",
+            "themeToggleAccessibilityLabel": themeToggleAccessibilityLabel,
+            "darkBackdropLayerCount": darkBackdropLayerCount,
+            "darkBackdropLayersVisible": darkBackdropLayersVisible,
+            "darkBackdropBackgroundGradientColors": backgroundGradientColorReports(),
+            "settingsButtonVisible": false,
             "spaceFocusAppGroupIndexes": spaceFocusedAppGroupIndexes(),
+            "appHoverAssociatedSpaceIDs": appHoverAssociatedSpaceIDs.sorted(),
+            "appHoverAssociatedSpaceLabels": appHoverAssociatedSpaceLabels,
+            "windowHoverAssociatedSpaceID": windowHoverAssociatedSpaceID ?? NSNull(),
             "lastSpaceFocusedAppGroupIndex": lastSpaceFocusedAppGroupIndex ?? NSNull(),
             "lastSpaceLaneClickSpaceID": lastSpaceLaneClickSpaceID ?? NSNull(),
             "lastAppShelfScrollSyncedAppGroupIndex": lastAppShelfScrollSyncedAppGroupIndex ?? NSNull(),
@@ -589,15 +1587,29 @@
             "appShelfHoverIconSize": Double(AppShelfMetrics.hoverIconSize),
             "appShelfSelectedIconSize": Double(AppShelfMetrics.selectedIconSize),
             "appShelfMinIconSize": Double(AppShelfMetrics.minIconSize),
+            "appShelfMagneticHoverEnabled": appShelfMagneticHoverEnabled,
+            "appShelfMagneticFirstNeighborInfluence": Double(AppShelfMetrics.magneticFirstNeighborInfluence),
+            "appShelfMagneticSecondNeighborInfluence": Double(AppShelfMetrics.magneticSecondNeighborInfluence),
+            "appShelfMagneticHoverLift": Double(AppShelfMetrics.magneticHoverLift),
+            "appShelfMagneticFirstNeighborLift": Double(AppShelfMetrics.magneticFirstNeighborLift),
+            "appShelfMagneticSecondNeighborLift": Double(AppShelfMetrics.magneticSecondNeighborLift),
+            "appShelfMagneticAnimationDurationMilliseconds": Double(AppShelfMetrics.magneticAnimationDuration * 1_000),
+            "appShelfMagneticAnimationTimingName": AppShelfMetrics.magneticAnimationTimingName.rawValue,
             "appShelfItems": appShelfItemReports(),
             "waterfallFrame": dictionary(from: waterfallLayer.frame),
+            "waterfallViewMode": waterfallViewMode.rawValue,
             "waterfallContentWidth": Double(waterfallContentWidth),
             "waterfallVisibleWidth": Double(waterfallLayer.bounds.width),
             "waterfallScrollOffset": Double(waterfallScrollOffset),
             "waterfallMaxScrollOffset": Double(waterfallMaxScrollOffset),
+            "horizontalMasonryContentHeight": Double(horizontalMasonryContentHeight),
+            "horizontalMasonryScrollOffset": Double(horizontalMasonryScrollOffset),
+            "horizontalMasonryMaxScrollOffset": Double(horizontalMasonryMaxScrollOffset),
+            "horizontalMasonryScrollable": horizontalMasonryMaxScrollOffset > 0,
             "waterfallAlignmentMinScrollOffset": Double(waterfallAlignmentScrollRange.lowerBound),
             "waterfallAlignmentMaxScrollOffset": Double(waterfallAlignmentScrollRange.upperBound),
-            "waterfallScrollable": waterfallAlignmentScrollable,
+            "waterfallScrollable": waterfallMaxScrollOffset > 0,
+            "waterfallAlignmentScrollable": waterfallAlignmentScrollable,
             "waterfallColumnCount": waterfallColumns.count,
             "waterfallColumnNames": waterfallColumns.map(\.column.app.name),
             "waterfallClipsToBounds": waterfallLayer.masksToBounds,
@@ -606,12 +1618,39 @@
             "waterfallAlignmentTolerance": Double(WaterfallAlignmentMetrics.tolerance),
             "waterfallAlignmentAnimationDurationMilliseconds": Double(WaterfallAlignmentMetrics.animationDuration * 1_000),
             "waterfallAlignmentAnimationTimingName": "easeOut",
+            "projectionTransitionMovedLayerCount": lastProjectionTransitionMovedLayerCount,
+            "projectionTransitionFadeInLayerCount": lastProjectionTransitionFadeInLayerCount,
+            "projectionTransitionFadeOutLayerCount": lastProjectionTransitionFadeOutLayerCount,
+            "projectionTransitionDurationMilliseconds": lastProjectionTransitionDurationMilliseconds,
             "reduceMotionEffective": NSWorkspace.shared.accessibilityDisplayShouldReduceMotion,
             "selectedAppGroupIndex": effectiveSelection?.appGroupIndex ?? NSNull(),
             "selectedWindowIndex": effectiveSelection?.windowIndex ?? NSNull(),
             "selectedWindowID": effectiveSelection?.windowID ?? NSNull(),
+            "keyboardFocusedAppGroupIndex": keyboardFocusedAppGroupIndex ?? NSNull(),
+            "keyboardFocusedWindowID": keyboardFocusedWindowID ?? NSNull(),
+            "horizontalAppDefaultWindowID": horizontalAppDefaultWindowID ?? NSNull(),
             "keyboardCommandsApplied": keyboardCommandsApplied,
             "lastKeyboardCommand": lastKeyboardCommand ?? NSNull(),
+            "lastKeyboardAppIndexCommand": lastKeyboardAppIndexCommand ?? NSNull(),
+            "appShelfIndexKeyDownCount": appShelfIndexKeyDownCount,
+            "lastAppShelfIndexKeySymbol": lastAppShelfIndexKeySymbol ?? NSNull(),
+            "windowIndexKeyPendingAppGroupIndex": windowIndexKeyPending?.appGroupIndex ?? NSNull(),
+            "windowIndexKeyPendingAppSymbol": windowIndexKeyPending?.appSymbol ?? NSNull(),
+            "lastWindowIndexKeyCommand": lastWindowIndexKeyCommand ?? NSNull(),
+            "lastWindowIndexKeyCommitCode": lastWindowIndexKeyCommitCode ?? NSNull(),
+            "windowShortcutFilterActive": shortcutFilterReport.active,
+            "windowShortcutFilterPhase": shortcutFilterReport.phase.rawValue,
+            "windowShortcutFilterPendingAppGroupIndex": shortcutFilterReport.pendingAppGroupIndex ?? NSNull(),
+            "windowShortcutFilterPrefix": shortcutFilterReport.prefix ?? NSNull(),
+            "windowShortcutFilterMatchedCount": shortcutFilterReport.matchedWindowIDs.count,
+            "windowShortcutFilterDimmedCount": shortcutFilterReport.dimmedWindowIDs.count,
+            "windowShortcutFilterMatchedWindowIDs": shortcutFilterReport.matchedWindowIDs.map(Int.init),
+            "windowShortcutFilterDimmedWindowIDs": shortcutFilterReport.dimmedWindowIDs.map(Int.init),
+            "lastWindowShortcutPreCommitFilterSnapshot": lastWindowShortcutPreCommitFilterSnapshot?.reportDictionary ?? NSNull(),
+            "lastBoundaryBounceAxis": lastBoundaryBounceAxis ?? NSNull(),
+            "lastBoundaryBounceDirection": lastBoundaryBounceDirection ?? NSNull(),
+            "boundaryBounceCount": boundaryBounceCount,
+            "selectionChangedByLastCommand": selectionChangedByLastCommand ?? NSNull(),
             "tabIgnoredCount": tabIgnoredCount,
             "lastCommittedAppGroupIndex": lastCommittedSelection?.appGroupIndex ?? NSNull(),
             "lastCommittedWindowIndex": lastCommittedSelection?.windowIndex ?? NSNull(),
@@ -627,6 +1666,13 @@
             "closeConfirmationVisible": !closeConfirmationLayers.containerLayer.isHidden,
             "closeConfirmationFrame": dictionary(from: closeConfirmationLayers.containerLayer.frame),
             "closeConfirmationArrowEdge": closeConfirmationArrowEdge?.rawValue ?? NSNull(),
+            "closeFeedbackVisible": closeFeedback != nil && !closeFeedbackLayer.isHidden,
+            "closeFeedbackKind": closeFeedback?.kind.rawValue ?? NSNull(),
+            "closeFeedbackMessage": closeFeedback?.message ?? NSNull(),
+            "closeFeedbackTargetKind": closeFeedback?.targetKind ?? NSNull(),
+            "closeFeedbackAppGroupIndex": closeFeedback?.appGroupIndex ?? NSNull(),
+            "closeFeedbackWindowID": closeFeedback?.windowID ?? NSNull(),
+            "closeFeedbackFrame": dictionary(from: closeFeedbackLayer.frame),
             "mouseCommandsApplied": mouseCommandsApplied,
             "lastMouseCommand": lastMouseCommand ?? NSNull(),
             "lastClickedAppGroupIndex": lastClickedAppGroupIndex ?? NSNull(),
@@ -677,27 +1723,68 @@
             .lowercased()
         guard !command.isEmpty else { return }
 
+        if let indexSymbol = appShelfIndexSymbol(fromKeyboardCommand: command) {
+            let recordedCommand = "app:\(indexSymbol)"
+            recordKeyboardCommand(recordedCommand)
+            clearWindowIndexKeyPending()
+            if !focusAppShelfItemForKeyboard(indexSymbol: indexSymbol, commandLabel: recordedCommand) {
+                selectionChangedByLastCommand = false
+            }
+            return
+        }
+
         switch command {
         case "left":
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("left")
-            moveSelection(.left)
+            if isHorizontalMasonryMode {
+                moveSelection(.left)
+            } else if !moveKeyboardAppFocus(cycleForward: false) {
+                selectionChangedByLastCommand = false
+            }
         case "right":
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("right")
-            moveSelection(.right)
+            if isHorizontalMasonryMode {
+                moveSelection(.right)
+            } else if !moveKeyboardAppFocus(cycleForward: true) {
+                selectionChangedByLastCommand = false
+            }
         case "up":
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("up")
-            moveSelection(.up)
+            if isHorizontalMasonryMode {
+                moveSelection(.up)
+            } else {
+                moveVerticalSelectionWithinFocusedColumn(.up)
+            }
         case "down":
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("down")
-            moveSelection(.down)
+            if isHorizontalMasonryMode {
+                moveSelection(.down)
+            } else {
+                moveVerticalSelectionWithinFocusedColumn(.down)
+            }
         case "enter", "return", "commit":
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("enter")
+            selectionChangedByLastCommand = false
             commitCurrentSelection()
         case "tab":
-            tabIgnoredCount += 1
-            recordKeyboardCommand("tabIgnored")
+            clearWindowIndexKeyPending()
+            if isHorizontalMasonryMode {
+                recordKeyboardCommand("tab")
+                moveHorizontalMasonryTabSelection()
+            } else {
+                tabIgnoredCount += 1
+                recordKeyboardCommand("tabIgnored")
+                selectionChangedByLastCommand = false
+            }
         default:
+            clearWindowIndexKeyPending()
             recordKeyboardCommand("unknown:\(command)")
+            selectionChangedByLastCommand = false
         }
     }
 
@@ -706,11 +1793,407 @@
         keyboardCommandsApplied.append(command)
     }
 
+    private func handleAppShelfIndexKey(_ event: NSEvent) -> Bool {
+        let flags = event.modifierFlags.intersection(.deviceIndependentFlagsMask)
+        guard flags.isDisjoint(with: [.command, .control]) else { return false }
+        guard let characters = event.charactersIgnoringModifiers,
+              let symbol = appShelfIndexSymbol(fromKeyboardCommand: characters)
+        else {
+            return false
+        }
+
+        appShelfIndexKeyDownCount += 1
+        lastAppShelfIndexKeySymbol = symbol
+        if flags.contains(.option), handleWindowIndexKey(symbol: symbol) {
+            return true
+        }
+        clearWindowIndexKeyPending()
+        performKeyboardCommand(symbol)
+        return true
+    }
+
+    private func handleWindowIndexKey(symbol: String) -> Bool {
+        let now = CACurrentMediaTime()
+        if let pending = validWindowIndexKeyPending(now: now) {
+            let code = "\(pending.appSymbol)\(symbol)"
+            if let card = waterfallCard(appGroupIndex: pending.appGroupIndex, windowIndexSymbol: symbol) {
+                recordKeyboardCommand("window:\(code)")
+                lastWindowIndexKeyCommand = "window:\(code)"
+                lastWindowIndexKeyCommitCode = code
+                lastWindowShortcutPreCommitFilterSnapshot = makeWindowShortcutPreCommitFilterSnapshot(
+                    target: card,
+                    code: code
+                )
+                windowShortcutFilterPhase = .targetPreCommit
+                clearWindowIndexKeyPending(resetShortcutFilter: false)
+                commitKeyboardWindowCard(card, trigger: "windowIndexKey")
+                return true
+            }
+
+            recordKeyboardCommand("windowInvalid:\(code)")
+            lastWindowIndexKeyCommand = "windowInvalid:\(code)"
+            lastWindowIndexKeyCommitCode = nil
+            windowShortcutFilterPhase = .invalid
+            lastWindowShortcutPreCommitFilterSnapshot = nil
+            selectionChangedByLastCommand = false
+            clearWindowIndexKeyPending(resetShortcutFilter: false)
+            return true
+        }
+
+        let recordedCommand = "app:\(symbol)"
+        recordKeyboardCommand(recordedCommand)
+        lastWindowIndexKeyCommand = nil
+        lastWindowIndexKeyCommitCode = nil
+        if focusAppShelfItemForKeyboard(indexSymbol: symbol, commandLabel: recordedCommand),
+           let ordinal = Self.appShelfIndexSymbols.firstIndex(of: symbol),
+           ordinal < appShelfItems.count {
+            let appGroupIndex = appShelfItems[ordinal].item.appGroupIndex
+            if let card = singleVisibleWaterfallCard(appGroupIndex: appGroupIndex) {
+                recordKeyboardCommand("windowSingle:\(symbol)")
+                lastWindowIndexKeyCommand = "windowSingle:\(symbol)"
+                lastWindowIndexKeyCommitCode = symbol
+                lastWindowShortcutPreCommitFilterSnapshot = nil
+                clearWindowIndexKeyPending()
+                commitKeyboardWindowCard(card, trigger: "windowIndexSingleApp")
+            } else {
+                setWindowIndexKeyPending(
+                    appSymbol: symbol,
+                    appGroupIndex: appGroupIndex,
+                    startedAt: now
+                )
+            }
+        } else {
+            selectionChangedByLastCommand = false
+            clearWindowIndexKeyPending()
+        }
+        return true
+    }
+
+    private func appShelfIndexSymbol(fromKeyboardCommand command: String) -> String? {
+        var candidate = command.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
+        for prefix in ["APP:", "APP-", "INDEX:", "INDEX-"] where candidate.hasPrefix(prefix) {
+            candidate.removeFirst(prefix.count)
+            break
+        }
+        guard candidate.count == 1,
+              Self.appShelfIndexSymbols.contains(candidate)
+        else {
+            return nil
+        }
+        return candidate
+    }
+
+    private func focusAppShelfItemForKeyboard(indexSymbol: String, commandLabel: String) -> Bool {
+        guard let ordinal = Self.appShelfIndexSymbols.firstIndex(of: indexSymbol),
+              ordinal < appShelfItems.count
+        else {
+            return false
+        }
+
+        return focusAppShelfItemForKeyboard(
+            appGroupIndex: appShelfItems[ordinal].item.appGroupIndex,
+            appIndexCommand: commandLabel
+        )
+    }
+
+    private func validWindowIndexKeyPending(now: CFTimeInterval) -> WindowIndexKeyPending? {
+        guard let pending = windowIndexKeyPending else { return nil }
+        guard now - pending.startedAt <= Self.windowIndexKeyPendingInterval else {
+            clearWindowIndexKeyPending()
+            return nil
+        }
+        return pending
+    }
+
+    private func setWindowIndexKeyPending(appSymbol: String, appGroupIndex: Int, startedAt: CFTimeInterval) {
+        windowIndexKeyPendingClearTask?.cancel()
+        windowIndexKeyPending = WindowIndexKeyPending(
+            appSymbol: appSymbol,
+            appGroupIndex: appGroupIndex,
+            startedAt: startedAt
+        )
+        windowShortcutFilterPhase = .appPending
+        lastWindowShortcutPreCommitFilterSnapshot = nil
+        needsLayout = true
+        windowIndexKeyPendingClearTask = Task { @MainActor [weak self] in
+            do {
+                try await Task.sleep(nanoseconds: UInt64(Self.windowIndexKeyPendingInterval * 1_000_000_000))
+            } catch {
+                return
+            }
+            guard let self,
+                  let pending = self.windowIndexKeyPending,
+                  pending.appSymbol == appSymbol,
+                  pending.appGroupIndex == appGroupIndex,
+                  pending.startedAt == startedAt
+            else {
+                return
+            }
+            self.windowIndexKeyPending = nil
+            self.windowIndexKeyPendingClearTask = nil
+            self.windowShortcutFilterPhase = .expired
+            self.lastWindowShortcutPreCommitFilterSnapshot = nil
+            self.needsLayout = true
+        }
+    }
+
+    private func clearWindowIndexKeyPending(resetShortcutFilter: Bool = true) {
+        let hadFilterState = windowIndexKeyPending != nil
+            || windowShortcutFilterPhase != .none
+            || lastWindowShortcutPreCommitFilterSnapshot != nil
+        windowIndexKeyPendingClearTask?.cancel()
+        windowIndexKeyPendingClearTask = nil
+        windowIndexKeyPending = nil
+        if resetShortcutFilter {
+            windowShortcutFilterPhase = .none
+            lastWindowShortcutPreCommitFilterSnapshot = nil
+        }
+        if hadFilterState {
+            needsLayout = true
+        }
+    }
+
+    @discardableResult
+    private func focusAppShelfItemForKeyboard(
+        appGroupIndex: Int,
+        appIndexCommand: String? = nil
+    ) -> Bool {
+        guard appShelfItems.contains(where: { $0.item.appGroupIndex == appGroupIndex }),
+              waterfallColumns.contains(where: { $0.column.appGroupIndex == appGroupIndex })
+        else {
+            return false
+        }
+
+        keyboardFocusedAppGroupIndex = appGroupIndex
+        keyboardFocusedWindowID = nil
+        lastKeyboardAppIndexCommand = appIndexCommand
+        selectionChangedByLastCommand = false
+        clearKeyboardBoundaryFeedback()
+        ensureAppShelfItemVisible(appGroupIndex)
+        layoutSubtreeIfNeeded()
+        if isHorizontalMasonryMode {
+            _ = selectHorizontalMasonryDefaultWindowForApp(appGroupIndex)
+        }
+        hoverAppGroup(appGroupIndex, source: .keyboard)
+        needsLayout = true
+        return true
+    }
+
+    @discardableResult
+    private func moveKeyboardAppFocus(cycleForward: Bool) -> Bool {
+        let orderedAppGroupIndexes = appShelfItems.map(\.item.appGroupIndex)
+        guard !orderedAppGroupIndexes.isEmpty else { return false }
+
+        let currentAppGroupIndex = keyboardFocusedAppGroupIndex
+            ?? appHoverTargetAppGroupIndex
+            ?? effectiveSelection?.appGroupIndex
+        let currentPosition = currentAppGroupIndex.flatMap { orderedAppGroupIndexes.firstIndex(of: $0) }
+        let nextPosition = currentPosition.map { current in
+            if cycleForward {
+                return (current + 1) % orderedAppGroupIndexes.count
+            }
+            return (current - 1 + orderedAppGroupIndexes.count) % orderedAppGroupIndexes.count
+        } ?? (cycleForward ? 0 : orderedAppGroupIndexes.count - 1)
+
+        return focusAppShelfItemForKeyboard(appGroupIndex: orderedAppGroupIndexes[nextPosition])
+    }
+
+    private var appHoverTargetAppGroupIndex: Int? {
+        guard case .app(let appGroupIndex) = hoverTarget else { return nil }
+        return appGroupIndex
+    }
+
+    private var horizontalAppDefaultWindowID: UInt32? {
+        guard isHorizontalMasonryMode,
+              case .app(let appGroupIndex) = hoverTarget
+        else {
+            return nil
+        }
+        return firstHorizontalMasonryCard(for: appGroupIndex)?.item.window.id
+    }
+
+    private func firstHorizontalMasonryCard(for appGroupIndex: Int) -> WaterfallCardLayers? {
+        waterfallColumns
+            .first { $0.column.appGroupIndex == appGroupIndex }?
+            .cards
+            .sorted { $0.item.windowIndex < $1.item.windowIndex }
+            .first
+    }
+
+    private func isHorizontalAppDefaultCard(_ card: WaterfallCardLayers) -> Bool {
+        guard isHorizontalMasonryMode,
+              card.item.window.id == horizontalAppDefaultWindowID
+        else {
+            return false
+        }
+        return true
+    }
+
+    @discardableResult
+    private func selectHorizontalMasonryDefaultWindowForApp(
+        _ appGroupIndex: Int,
+        recordsSelectionChange: Bool = false
+    ) -> QuickSwitchSelection? {
+        guard isHorizontalMasonryMode,
+              let card = firstHorizontalMasonryCard(for: appGroupIndex)
+        else {
+            return nil
+        }
+
+        let previousSelection = effectiveSelection
+        let selection = selectionForCard(card)
+        currentSelection = selection
+        columnSelectionHistory[selection.appGroupIndex] = selection.windowIndex
+        if recordsSelectionChange {
+            selectionChangedByLastCommand = previousSelection != selection
+        }
+        return selection
+    }
+
+    private func moveVerticalSelectionWithinFocusedColumn(_ direction: QuickSwitchKeyboardDirection) {
+        guard direction == .up || direction == .down,
+              let targetAppGroupIndex = verticalKeyboardNavigationAppGroupIndex(),
+              let column = waterfallColumns.first(where: { $0.column.appGroupIndex == targetAppGroupIndex })
+        else {
+            DevelopmentDiagnostics.log("quickSwitch.view.moveVerticalSelection.blocked", [
+                "direction": keyboardDirectionName(direction),
+                "hasFocusedApp": keyboardFocusedAppGroupIndex != nil,
+                "hasSelection": effectiveSelection != nil
+            ])
+            selectionChangedByLastCommand = false
+            return
+        }
+
+        let cards = column.cards.sorted { $0.item.windowIndex < $1.item.windowIndex }
+        guard !cards.isEmpty else {
+            selectionChangedByLastCommand = false
+            return
+        }
+
+        let previousSelection = effectiveSelection
+        let nextSelection: QuickSwitchSelection
+        if let current = previousSelection,
+           current.appGroupIndex == targetAppGroupIndex,
+           let currentPosition = cards.firstIndex(where: { $0.item.window.id == current.windowID }) {
+            let nextPosition = currentPosition + (direction == .down ? 1 : -1)
+            guard cards.indices.contains(nextPosition) else {
+                keyboardFocusedAppGroupIndex = targetAppGroupIndex
+                hoverAppGroup(targetAppGroupIndex, source: .keyboard)
+                triggerKeyboardBoundaryFeedback(appGroupIndex: targetAppGroupIndex, direction: direction)
+                DevelopmentDiagnostics.log("quickSwitch.view.moveVerticalSelection.boundary", [
+                    "direction": keyboardDirectionName(direction),
+                    "appGroupIndex": targetAppGroupIndex,
+                    "windowIndex": current.windowIndex
+                ])
+                needsLayout = true
+                return
+            }
+            nextSelection = selectionForCard(cards[nextPosition])
+        } else {
+            let rememberedWindowIndex = columnSelectionHistory[targetAppGroupIndex]
+            let rememberedCard = rememberedWindowIndex.flatMap { windowIndex in
+                cards.first { $0.item.windowIndex == windowIndex }
+            }
+            nextSelection = selectionForCard(rememberedCard ?? cards[0])
+        }
+
+        keyboardFocusedAppGroupIndex = targetAppGroupIndex
+        currentSelection = nextSelection
+        keyboardFocusedWindowID = nextSelection.windowID
+        columnSelectionHistory[nextSelection.appGroupIndex] = nextSelection.windowIndex
+        selectionChangedByLastCommand = previousSelection != nextSelection
+        clearKeyboardBoundaryFeedback()
+        hoverAppGroup(targetAppGroupIndex, source: .keyboard)
+        ensureCurrentSelectionVisible(horizontalIntent: .alignWithAppShelf(animated: true))
+        DevelopmentDiagnostics.log("quickSwitch.view.moveVerticalSelection", [
+            "direction": keyboardDirectionName(direction),
+            "appGroupIndex": nextSelection.appGroupIndex,
+            "windowIndex": nextSelection.windowIndex,
+            "windowID": nextSelection.windowID
+        ])
+        needsLayout = true
+    }
+
+    private func verticalKeyboardNavigationAppGroupIndex() -> Int? {
+        if let keyboardFocusedAppGroupIndex,
+           waterfallColumns.contains(where: { $0.column.appGroupIndex == keyboardFocusedAppGroupIndex }) {
+            return keyboardFocusedAppGroupIndex
+        }
+        if let appHoverTargetAppGroupIndex,
+           waterfallColumns.contains(where: { $0.column.appGroupIndex == appHoverTargetAppGroupIndex }) {
+            return appHoverTargetAppGroupIndex
+        }
+        if let appGroupIndex = effectiveSelection?.appGroupIndex,
+           waterfallColumns.contains(where: { $0.column.appGroupIndex == appGroupIndex }) {
+            return appGroupIndex
+        }
+        return waterfallColumns.first?.column.appGroupIndex
+    }
+
+    private func clearKeyboardBoundaryFeedback() {
+        lastBoundaryBounceAxis = nil
+        lastBoundaryBounceDirection = nil
+    }
+
+    private func triggerKeyboardBoundaryFeedback(
+        appGroupIndex: Int,
+        direction: QuickSwitchKeyboardDirection
+    ) {
+        selectionChangedByLastCommand = false
+        lastBoundaryBounceAxis = "vertical"
+        lastBoundaryBounceDirection = keyboardDirectionName(direction)
+        boundaryBounceCount += 1
+
+        layoutSubtreeIfNeeded()
+        guard let column = waterfallColumns.first(where: { $0.column.appGroupIndex == appGroupIndex }) else { return }
+
+        let animationKey = "keyboardBoundaryBounce"
+        column.containerLayer.removeAnimation(forKey: animationKey)
+        if NSWorkspace.shared.accessibilityDisplayShouldReduceMotion {
+            let pulse = CABasicAnimation(keyPath: "opacity")
+            pulse.fromValue = 1
+            pulse.toValue = 0.9
+            pulse.duration = 0.12
+            pulse.autoreverses = true
+            pulse.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
+            column.containerLayer.add(pulse, forKey: animationKey)
+            return
+        }
+
+        let currentY = column.containerLayer.presentation()?.position.y
+            ?? column.containerLayer.position.y
+        let delta: CGFloat = direction == .up ? 5 : -5
+        let bounce = CAKeyframeAnimation(keyPath: "position.y")
+        bounce.values = [currentY, currentY + delta, currentY]
+        bounce.keyTimes = [0, 0.38, 1]
+        bounce.timingFunctions = [
+            CAMediaTimingFunction(name: .easeOut),
+            CAMediaTimingFunction(name: .easeInEaseOut)
+        ]
+        bounce.duration = 0.23
+        bounce.isRemovedOnCompletion = true
+        column.containerLayer.add(bounce, forKey: animationKey)
+    }
+
+    private func keyboardDirectionName(_ direction: QuickSwitchKeyboardDirection) -> String {
+        switch direction {
+        case .left:
+            return "left"
+        case .right:
+            return "right"
+        case .up:
+            return "up"
+        case .down:
+            return "down"
+        }
+    }
+
     private func performMouseCommand(_ rawCommand: String) {
         let command = rawCommand
             .trimmingCharacters(in: .whitespacesAndNewlines)
             .lowercased()
         guard !command.isEmpty else { return }
+        clearWindowIndexKeyPending()
 
         let parts = command.split(separator: ":").map(String.init)
         switch parts.first {
@@ -721,6 +2204,11 @@
             }
             recordMouseCommand("hover-app:\(appGroupIndex)")
             hoverAppGroup(appGroupIndex)
+        case "reapply-view-model":
+            if let currentViewModel {
+                apply(viewModel: currentViewModel)
+            }
+            recordMouseCommand("reapply-view-model")
         case "click-app" where parts.count == 2:
             guard let appGroupIndex = Int(parts[1]) else {
                 recordMouseCommand("invalid:\(command)")
@@ -728,6 +2216,20 @@
             }
             recordMouseCommand("click-app:\(appGroupIndex)")
             clickAppShelfItem(appGroupIndex: appGroupIndex)
+        case "click-app-center" where parts.count == 2:
+            guard let appGroupIndex = Int(parts[1]) else {
+                recordMouseCommand("invalid:\(command)")
+                return
+            }
+            recordMouseCommand("click-app-center:\(appGroupIndex)")
+            clickAppShelfItemViaMouse(appGroupIndex: appGroupIndex, probe: .iconCenter)
+        case "click-app-near-close" where parts.count == 2:
+            guard let appGroupIndex = Int(parts[1]) else {
+                recordMouseCommand("invalid:\(command)")
+                return
+            }
+            recordMouseCommand("click-app-near-close:\(appGroupIndex)")
+            clickAppShelfItemViaMouse(appGroupIndex: appGroupIndex, probe: .nearCloseOutsideHit)
         case "hover-app-close" where parts.count == 2:
             guard let appGroupIndex = Int(parts[1]) else {
                 recordMouseCommand("invalid:\(command)")
@@ -756,7 +2258,7 @@
             }
             recordMouseCommand("hover-space:\(spaceID)")
             if let segment = spaceLaneSegment(spaceID: spaceID) {
-                hoverSpaceLaneSegment(segment)
+                hoverSpaceLaneSegment(segment, source: .debug)
             }
         case "click-space" where parts.count == 2:
             guard let spaceID = UInt64(parts[1]) else {
@@ -765,8 +2267,41 @@
             }
             recordMouseCommand("click-space:\(spaceID)")
             if let segment = spaceLaneSegment(spaceID: spaceID) {
-                clickSpaceLaneSegment(segment)
+                clickSpaceLaneSegment(segment, clickCount: 1)
             }
+        case "double-click-space" where parts.count == 2:
+            guard let spaceID = UInt64(parts[1]) else {
+                recordMouseCommand("invalid:\(command)")
+                return
+            }
+            recordMouseCommand("double-click-space:\(spaceID)")
+            if let segment = spaceLaneSegment(spaceID: spaceID) {
+                clickSpaceLaneSegment(segment, clickCount: 1)
+                clickSpaceLaneSegment(segment, clickCount: 2)
+            }
+        case "click-background":
+            recordMouseCommand("click-background")
+            _ = onBackgroundClick?()
+        case "hover-view-toggle":
+            recordMouseCommand("hover-view-toggle")
+            suppressViewModeToggleHoverPreview = false
+            isViewModeToggleButtonHovered = true
+            isThemeToggleButtonHovered = false
+            hoveredCloseTarget = nil
+            setHoverTarget(.none, source: .debug)
+        case "click-view-toggle", "click-settings":
+            recordMouseCommand("click-view-toggle")
+            clickViewModeToggleButton(source: "debug")
+        case "hover-theme-toggle":
+            recordMouseCommand("hover-theme-toggle")
+            suppressThemeToggleHoverPreview = false
+            isThemeToggleButtonHovered = true
+            isViewModeToggleButtonHovered = false
+            hoveredCloseTarget = nil
+            setHoverTarget(.none, source: .debug)
+        case "click-theme-toggle":
+            recordMouseCommand("click-theme-toggle")
+            clickThemeToggleButton(source: "debug")
         case "hover-card" where parts.count == 3:
             guard let appGroupIndex = Int(parts[1]), let windowIndex = Int(parts[2]) else {
                 recordMouseCommand("invalid:\(command)")
@@ -774,7 +2309,7 @@
             }
             recordMouseCommand("hover-card:\(appGroupIndex):\(windowIndex)")
             if let card = waterfallCard(appGroupIndex: appGroupIndex, windowIndex: windowIndex) {
-                hoverWindowCard(card)
+                hoverWindowCard(card, source: .debug)
             }
         case "click-card" where parts.count == 3:
             guard let appGroupIndex = Int(parts[1]), let windowIndex = Int(parts[2]) else {
@@ -783,6 +2318,15 @@
             }
             recordMouseCommand("click-card:\(appGroupIndex):\(windowIndex)")
             if let card = waterfallCard(appGroupIndex: appGroupIndex, windowIndex: windowIndex) {
+                clickWindowCard(card)
+            }
+        case "click-card-id" where parts.count == 2:
+            guard let windowID = UInt32(parts[1]) else {
+                recordMouseCommand("invalid:\(command)")
+                return
+            }
+            recordMouseCommand("click-card-id:\(windowID)")
+            if let card = waterfallCard(windowID: windowID) {
                 clickWindowCard(card)
             }
         case "hover-card-close" where parts.count == 3:
@@ -825,14 +2369,14 @@
         return command.hasPrefix("hover-")
     }
 
-    private func hoverAppGroup(_ appGroupIndex: Int) {
-        hoveredSpaceLaneID = nil
-        hoveredCloseTarget = nil
+    private func hoverAppGroup(_ appGroupIndex: Int, source: HoverTargetSource = .debug) {
+        lastKnownMouseWindowLocation = appShelfItemCenterWindowLocation(for: appGroupIndex)
         updateHoverState(
             appGroupIndex: appGroupIndex,
             windowID: nil,
             spaceID: nil,
-            alignsWaterfallWithAppShelf: true
+            alignsWaterfallWithAppShelf: true,
+            source: source
         )
     }
 
@@ -847,19 +2391,18 @@
         beginCloseConfirmation(for: .app(appGroupIndex: appGroupIndex))
     }
 
-    private func hoverWindowCard(_ card: WaterfallCardLayers) {
-        hoveredSpaceLaneID = nil
-        hoveredCloseTarget = nil
+    private func hoverWindowCard(_ card: WaterfallCardLayers, source: HoverTargetSource = .event) {
         updateHoverState(
             appGroupIndex: card.item.appGroupIndex,
             windowID: card.item.window.id,
-            spaceID: card.item.primarySpaceID
+            spaceID: card.item.primarySpaceID,
+            source: source
         )
     }
 
     private func hoverCardCloseButton(appGroupIndex: Int, windowIndex: Int) {
         guard let card = waterfallCard(appGroupIndex: appGroupIndex, windowIndex: windowIndex) else { return }
-        hoverWindowCard(card)
+        hoverWindowCard(card, source: .debug)
         hoveredCloseTarget = .window(
             appGroupIndex: appGroupIndex,
             windowIndex: windowIndex,
@@ -880,33 +2423,23 @@
         )
     }
 
-    private func hoverSpaceLaneSegment(_ segment: SpaceLaneSegmentLayers) {
-        focusSpace(segment.space.id, persistent: false)
+    private func hoverSpaceLaneSegment(_ segment: SpaceLaneSegmentLayers, source: HoverTargetSource = .event) {
+        focusSpace(segment.space.id, persistent: false, source: source)
     }
 
-    private func clickSpaceLaneSegment(_ segment: SpaceLaneSegmentLayers) {
+    private func clickSpaceLaneSegment(_ segment: SpaceLaneSegmentLayers, clickCount: Int = 1) {
         DevelopmentDiagnostics.log("quickSwitch.view.clickSpaceLane", [
             "spaceID": segment.space.id,
-            "label": segment.space.label
+            "label": segment.space.label,
+            "clickCount": clickCount
         ])
         lastSpaceLaneClickSpaceID = segment.space.id
-
-        guard let firstCard = firstWaterfallCard(inSpaceID: segment.space.id) else {
-            DevelopmentDiagnostics.log("quickSwitch.view.clickSpaceLane.emptySpaceUnsupported", [
-                "spaceID": segment.space.id,
-                "label": segment.space.label
-            ])
-            return
-        }
-
-        commitWindowCard(firstCard, trigger: "spaceLane")
+        onSpaceLaneClick?(segment.space.id, clickCount)
+        lastSpaceLaneClickSpaceID = segment.space.id
     }
 
-    private func focusSpace(_ spaceID: UInt64, persistent: Bool) {
-        hoveredAppGroupIndex = nil
-        hoveredWindowID = nil
-        hoveredSpaceID = spaceID
-        hoveredSpaceLaneID = spaceID
+    private func focusSpace(_ spaceID: UInt64, persistent: Bool, source: HoverTargetSource = .event) {
+        setHoverTarget(.space(spaceID), source: source)
         if persistent {
             focusedSpaceID = spaceID
             lastSpaceLaneClickSpaceID = spaceID
@@ -960,6 +2493,64 @@
         }
     }
 
+    private enum AppShelfMouseClickProbe {
+        case iconCenter
+        case nearCloseOutsideHit
+    }
+
+    private func clickAppShelfItemViaMouse(appGroupIndex: Int, probe: AppShelfMouseClickProbe) {
+        guard let windowLocation = appShelfSyntheticMouseDownLocation(for: appGroupIndex, probe: probe) else {
+            DevelopmentDiagnostics.log("quickSwitch.view.clickAppShelfViaMouse.missingLocation", [
+                "appGroupIndex": appGroupIndex
+            ])
+            return
+        }
+        _ = handleMouseDown(at: windowLocation, clickCount: 1, allowBackgroundClick: false)
+    }
+
+    private func appShelfSyntheticMouseDownLocation(
+        for appGroupIndex: Int,
+        probe: AppShelfMouseClickProbe
+    ) -> CGPoint? {
+        layoutSubtreeIfNeeded()
+        guard let item = appShelfItems.first(where: { $0.item.appGroupIndex == appGroupIndex }) else {
+            return nil
+        }
+
+        let iconFrame = item.iconLayer.frame
+        let closeFrame = item.closeButton.containerLayer.frame
+        let pointInItem: CGPoint
+        switch probe {
+        case .iconCenter:
+            pointInItem = CGPoint(x: iconFrame.midX, y: iconFrame.midY)
+        case .nearCloseOutsideHit:
+            let fallbackPoint = CGPoint(
+                x: iconFrame.maxX - 4,
+                y: iconFrame.maxY - 14
+            )
+            if closeFrame.width > 0, closeFrame.height > 0 {
+                let candidate = CGPoint(x: closeFrame.minX - 4, y: closeFrame.midY)
+                pointInItem = iconFrame.contains(candidate) ? candidate : fallbackPoint
+            } else {
+                pointInItem = fallbackPoint
+            }
+        }
+
+        let pointInView = CGPoint(
+            x: glassLayer.frame.minX
+                + shelfLayer.frame.minX
+                + appShelfContentLayer.frame.minX
+                + item.containerLayer.frame.minX
+                + pointInItem.x,
+            y: glassLayer.frame.minY
+                + shelfLayer.frame.minY
+                + appShelfContentLayer.frame.minY
+                + item.containerLayer.frame.minY
+                + pointInItem.y
+        )
+        return convert(pointInView, to: nil)
+    }
+
     private func scrollAppShelf(to targetOffset: CGFloat) {
         layoutSubtreeIfNeeded()
         let previousOffset = appShelfScrollOffset
@@ -1002,6 +2593,34 @@
         commitWindowCard(card, trigger: "windowCard")
     }
 
+    private func commitKeyboardWindowCard(_ card: WaterfallCardLayers, trigger: String) {
+        let selection = QuickSwitchSelection(
+            appGroupIndex: card.item.appGroupIndex,
+            windowIndex: card.item.windowIndex,
+            windowID: card.item.window.id
+        )
+        DevelopmentDiagnostics.log("quickSwitch.view.commitKeyboardWindow", [
+            "trigger": trigger,
+            "appGroupIndex": selection.appGroupIndex,
+            "windowIndex": selection.windowIndex,
+            "windowID": selection.windowID,
+            "appName": card.item.window.app.name,
+            "appPID": card.item.window.app.processIdentifier,
+            "titleHash": DevelopmentDiagnostics.stableFingerprint(card.item.window.title),
+            "titleLength": card.item.window.title.count,
+            "titleIsEmpty": card.item.window.title.isEmpty,
+            "isMinimized": card.item.window.isMinimized,
+            "isFullscreen": card.item.window.isFullscreen,
+            "identifierSource": String(describing: card.item.window.identifierSource)
+        ])
+        currentSelection = selection
+        columnSelectionHistory[selection.appGroupIndex] = selection.windowIndex
+        lastCommittedSelection = selection
+        lastCommitSource = .keyboard
+        ensureCurrentSelectionVisible()
+        onCommitSelection?(selection, .keyboard)
+    }
+
     private func commitWindowCard(_ card: WaterfallCardLayers, trigger: String) {
         let selection = QuickSwitchSelection(
             appGroupIndex: card.item.appGroupIndex,
@@ -1035,28 +2654,99 @@
         appGroupIndex: Int?,
         windowID: UInt32?,
         spaceID: UInt64?,
-        alignsWaterfallWithAppShelf: Bool = false
+        alignsWaterfallWithAppShelf: Bool = false,
+        source: HoverTargetSource = .event
     ) {
-        guard hoveredAppGroupIndex != appGroupIndex
-            || hoveredWindowID != windowID
-            || hoveredSpaceID != spaceID
-        else {
-            if alignsWaterfallWithAppShelf, let appGroupIndex {
-                alignWaterfallColumnWithAppShelfIcon(appGroupIndex: appGroupIndex, animated: true)
-            }
+        let target: HoverTarget
+        if let appGroupIndex, let windowID {
+            target = .window(appGroupIndex: appGroupIndex, windowID: windowID, spaceID: spaceID)
+        } else if let appGroupIndex {
+            target = .app(appGroupIndex)
+        } else {
+            target = .none
+        }
+
+        setHoverTarget(target, source: source, alignsWaterfallWithAppShelf: alignsWaterfallWithAppShelf)
+    }
+
+    private func refreshHoverTarget(at windowLocation: CGPoint) {
+        guard debugHoveredAppGroupIndex == nil else { return }
+        lastKnownMouseWindowLocation = windowLocation
+        let target = resolveHoverTarget(at: windowLocation)
+        setHoverTarget(target, alignsWaterfallWithAppShelf: target.shouldAlignWaterfallWithAppShelf)
+    }
+
+    private func refreshHoverTargetAfterViewRebuild() {
+        guard debugHoveredAppGroupIndex == nil, currentViewModel != nil else { return }
+
+        layoutSubtreeIfNeeded()
+        let windowLocation = lastKnownMouseWindowLocation ?? window?.mouseLocationOutsideOfEventStream
+        guard let windowLocation else { return }
+
+        let locationInView = convert(windowLocation, from: nil)
+        guard bounds.contains(locationInView) else {
+            lastKnownMouseWindowLocation = nil
+            setHoverTarget(.none)
             return
         }
 
-        hoveredAppGroupIndex = appGroupIndex
-        hoveredWindowID = windowID
-        hoveredSpaceID = spaceID
-        if alignsWaterfallWithAppShelf, let appGroupIndex {
+        refreshHoverTarget(at: windowLocation)
+    }
+
+    private func resolveHoverTarget(at windowLocation: CGPoint) -> HoverTarget {
+        if let segment = spaceLaneSegment(at: windowLocation) {
+            return .space(segment.space.id)
+        }
+
+        if let card = waterfallCard(at: windowLocation) {
+            return .window(
+                appGroupIndex: card.item.appGroupIndex,
+                windowID: card.item.window.id,
+                spaceID: card.item.primarySpaceID
+            )
+        }
+
+        if let item = appShelfItem(at: windowLocation) {
+            return .app(item.item.appGroupIndex)
+        }
+
+        return .none
+    }
+
+    private func setHoverTarget(
+        _ target: HoverTarget,
+        source: HoverTargetSource = .event,
+        alignsWaterfallWithAppShelf: Bool = false
+    ) {
+        let previousTarget = hoverTarget
+        let previousSource = hoverTargetSource
+        hoverTarget = target
+        hoverTargetSource = source
+
+        hoveredAppGroupIndex = target.appGroupIndex
+        hoveredWindowID = target.windowID
+        hoveredSpaceID = target.spaceID
+        hoveredSpaceLaneID = target.spaceLaneID
+
+        if case .app(let appGroupIndex) = target, isHorizontalMasonryMode {
+            keyboardFocusedWindowID = nil
+            _ = selectHorizontalMasonryDefaultWindowForApp(appGroupIndex)
+        }
+
+        if alignsWaterfallWithAppShelf, let appGroupIndex = target.appGroupIndex {
             alignWaterfallColumnWithAppShelfIcon(appGroupIndex: appGroupIndex, animated: true)
         }
+
+        guard previousTarget != target || previousSource != source else { return }
         needsLayout = true
     }
 
     private func moveSelection(_ direction: QuickSwitchKeyboardDirection) {
+        if isHorizontalMasonryMode {
+            moveHorizontalMasonrySelection(direction)
+            return
+        }
+
         guard let currentViewModel,
               let snapshot = snapshotForFocus(from: currentViewModel),
               let current = currentSelection ?? currentViewModel.initialSelection,
@@ -1076,8 +2766,11 @@
         }
 
         columnSelectionHistory[current.appGroupIndex] = current.windowIndex
+        let previousSelection = effectiveSelection
         currentSelection = next
         columnSelectionHistory[next.appGroupIndex] = next.windowIndex
+        selectionChangedByLastCommand = previousSelection != next
+        clearKeyboardBoundaryFeedback()
         ensureCurrentSelectionVisible(horizontalIntent: .alignWithAppShelf(animated: true))
         DevelopmentDiagnostics.log("quickSwitch.view.moveSelection", [
             "direction": String(describing: direction),
@@ -1086,6 +2779,447 @@
             "windowID": next.windowID
         ])
         needsLayout = true
+    }
+
+    private func moveHorizontalMasonrySelection(_ direction: QuickSwitchKeyboardDirection) {
+        layoutSubtreeIfNeeded()
+
+        let nodes = horizontalKeyboardFocusNodes()
+        guard !nodes.isEmpty,
+              let current = currentHorizontalKeyboardFocusNode(in: nodes),
+              let next = nextHorizontalKeyboardFocusNode(from: current, direction: direction, in: nodes)
+        else {
+            DevelopmentDiagnostics.log("quickSwitch.view.moveHorizontalMasonrySelection.blocked", [
+                "direction": String(describing: direction),
+                "hasNodes": !nodes.isEmpty,
+                "hasSelection": (currentSelection ?? currentViewModel?.initialSelection) != nil
+            ])
+            selectionChangedByLastCommand = false
+            return
+        }
+
+        focusHorizontalKeyboardNode(next, direction: direction)
+        DevelopmentDiagnostics.log("quickSwitch.view.moveHorizontalMasonrySelection", [
+            "direction": String(describing: direction),
+            "kind": next.kind.rawValue,
+            "appGroupIndex": next.appGroupIndex,
+            "windowIndex": next.windowIndex ?? -1,
+            "windowID": next.windowID ?? 0
+        ])
+    }
+
+    private func moveHorizontalMasonryTabSelection() {
+        guard let current = currentSelection ?? currentViewModel?.initialSelection,
+              let next = nextHorizontalMasonrySelection(from: current, direction: .right)
+        else {
+            DevelopmentDiagnostics.log("quickSwitch.view.moveHorizontalMasonryTabSelection.blocked", [
+                "hasSelection": (currentSelection ?? currentViewModel?.initialSelection) != nil
+            ])
+            selectionChangedByLastCommand = false
+            return
+        }
+
+        columnSelectionHistory[current.appGroupIndex] = current.windowIndex
+        let previousSelection = effectiveSelection
+        currentSelection = next
+        keyboardFocusedAppGroupIndex = next.appGroupIndex
+        keyboardFocusedWindowID = next.windowID
+        columnSelectionHistory[next.appGroupIndex] = next.windowIndex
+        selectionChangedByLastCommand = previousSelection != next
+        clearKeyboardBoundaryFeedback()
+        setHoverTarget(
+            .window(appGroupIndex: next.appGroupIndex, windowID: next.windowID, spaceID: nil),
+            source: .keyboard
+        )
+        ensureCurrentSelectionVisible(horizontalIntent: .alignWithAppShelf(animated: true))
+        DevelopmentDiagnostics.log("quickSwitch.view.moveHorizontalMasonryTabSelection", [
+            "appGroupIndex": next.appGroupIndex,
+            "windowIndex": next.windowIndex,
+            "windowID": next.windowID
+        ])
+        needsLayout = true
+    }
+
+    private func horizontalKeyboardFocusNodes() -> [HorizontalKeyboardFocusNode] {
+        var nodes: [HorizontalKeyboardFocusNode] = []
+        nodes.reserveCapacity(appShelfItems.count + waterfallColumns.reduce(0) { $0 + $1.cards.count })
+
+        for (index, item) in appShelfItems.enumerated() {
+            let frame = item.iconLayer.frame.offsetBy(
+                dx: shelfLayer.frame.minX
+                    + appShelfContentLayer.frame.minX
+                    + item.containerLayer.frame.minX,
+                dy: shelfLayer.frame.minY
+                    + appShelfContentLayer.frame.minY
+                    + item.containerLayer.frame.minY
+            )
+            nodes.append(HorizontalKeyboardFocusNode(
+                kind: .app,
+                appGroupIndex: item.item.appGroupIndex,
+                windowIndex: nil,
+                windowID: nil,
+                spaceID: nil,
+                frame: frame,
+                order: index
+            ))
+        }
+
+        var order = appShelfItems.count
+        for column in waterfallColumns.sorted(by: { $0.column.appGroupIndex < $1.column.appGroupIndex }) {
+            for card in column.cards.sorted(by: { $0.item.windowIndex < $1.item.windowIndex }) {
+                let frame = card.containerLayer.frame.offsetBy(
+                    dx: waterfallLayer.frame.minX
+                        + waterfallContentLayer.frame.minX
+                        + column.containerLayer.frame.minX
+                        + column.cardsClipLayer.frame.minX,
+                    dy: waterfallLayer.frame.minY
+                        + waterfallContentLayer.frame.minY
+                        + column.containerLayer.frame.minY
+                        + column.cardsClipLayer.frame.minY
+                )
+                nodes.append(HorizontalKeyboardFocusNode(
+                    kind: .window,
+                    appGroupIndex: card.item.appGroupIndex,
+                    windowIndex: card.item.windowIndex,
+                    windowID: card.item.window.id,
+                    spaceID: card.item.primarySpaceID,
+                    frame: frame,
+                    order: order
+                ))
+                order += 1
+            }
+        }
+
+        return nodes
+    }
+
+    private func currentHorizontalKeyboardFocusNode(
+        in nodes: [HorizontalKeyboardFocusNode]
+    ) -> HorizontalKeyboardFocusNode? {
+        if case .app(let appGroupIndex) = hoverTarget,
+           let node = nodes.first(where: { $0.kind == .app && $0.appGroupIndex == appGroupIndex }) {
+            return node
+        }
+
+        if let keyboardFocusedWindowID,
+           let node = nodes.first(where: { $0.kind == .window && $0.windowID == keyboardFocusedWindowID }) {
+            return node
+        }
+
+        if case .window(_, let windowID, _) = hoverTarget,
+           let node = nodes.first(where: { $0.kind == .window && $0.windowID == windowID }) {
+            return node
+        }
+
+        if let selection = effectiveSelection,
+           let node = nodes.first(where: { $0.kind == .window && $0.windowID == selection.windowID }) {
+            return node
+        }
+
+        return nodes.min { $0.order < $1.order }
+    }
+
+    private func nextHorizontalKeyboardFocusNode(
+        from current: HorizontalKeyboardFocusNode,
+        direction: QuickSwitchKeyboardDirection,
+        in nodes: [HorizontalKeyboardFocusNode]
+    ) -> HorizontalKeyboardFocusNode? {
+        let candidates = nodes.filter { !$0.matches(current) }
+        guard !candidates.isEmpty else { return current }
+
+        if current.kind == .app,
+           direction == .down,
+           let firstWindow = firstHorizontalWindowNode(for: current.appGroupIndex, in: nodes) {
+            return firstWindow
+        }
+
+        if current.kind == .window,
+           direction == .up,
+           current.windowID == firstHorizontalMasonryCard(for: current.appGroupIndex)?.item.window.id,
+           let appNode = nodes.first(where: { $0.kind == .app && $0.appGroupIndex == current.appGroupIndex }) {
+            return appNode
+        }
+
+        switch direction {
+        case .left, .right:
+            let sameKindCandidates = candidates.filter { $0.kind == current.kind }
+            return nextHorizontalFocusByX(
+                from: current,
+                direction: direction,
+                candidates: sameKindCandidates.isEmpty ? candidates : sameKindCandidates
+            )
+        case .up, .down:
+            return nextHorizontalFocusByY(from: current, direction: direction, candidates: candidates)
+        }
+    }
+
+    private func firstHorizontalWindowNode(
+        for appGroupIndex: Int,
+        in nodes: [HorizontalKeyboardFocusNode]
+    ) -> HorizontalKeyboardFocusNode? {
+        nodes
+            .filter { $0.kind == .window && $0.appGroupIndex == appGroupIndex }
+            .min { lhs, rhs in
+                (lhs.windowIndex ?? .max, lhs.order) < (rhs.windowIndex ?? .max, rhs.order)
+            }
+    }
+
+    private func nextHorizontalFocusByX(
+        from current: HorizontalKeyboardFocusNode,
+        direction: QuickSwitchKeyboardDirection,
+        candidates: [HorizontalKeyboardFocusNode]
+    ) -> HorizontalKeyboardFocusNode? {
+        let epsilon: CGFloat = 0.5
+        let forward = direction == .right
+        let directional = candidates.filter { node in
+            forward
+                ? node.center.x > current.center.x + epsilon
+                : node.center.x < current.center.x - epsilon
+        }
+        let sameBand = directional.filter { isHorizontalFocusSameBand($0, current) }
+        let pool = sameBand.isEmpty ? directional : sameBand
+        if let next = pool.sorted(by: horizontalFocusXSort(from: current, forward: forward)).first {
+            return next
+        }
+
+        let wrapSameBand = candidates.filter { isHorizontalFocusSameBand($0, current) }
+        let wrapPool = wrapSameBand.isEmpty ? candidates : wrapSameBand
+        return wrapPool.sorted(by: horizontalFocusXWrapSort(from: current, forward: forward)).first
+    }
+
+    private func nextHorizontalFocusByY(
+        from current: HorizontalKeyboardFocusNode,
+        direction: QuickSwitchKeyboardDirection,
+        candidates: [HorizontalKeyboardFocusNode]
+    ) -> HorizontalKeyboardFocusNode? {
+        let epsilon: CGFloat = 0.5
+        let upward = direction == .up
+        let directional = candidates.filter { node in
+            upward
+                ? node.center.y > current.center.y + epsilon
+                : node.center.y < current.center.y - epsilon
+        }
+        if let next = directional.sorted(by: horizontalFocusYSort(from: current, upward: upward)).first {
+            return next
+        }
+        return candidates.sorted(by: horizontalFocusYWrapSort(from: current, upward: upward)).first
+    }
+
+    private func isHorizontalFocusSameBand(
+        _ lhs: HorizontalKeyboardFocusNode,
+        _ rhs: HorizontalKeyboardFocusNode
+    ) -> Bool {
+        let tolerance = max(lhs.frame.height, rhs.frame.height) * 0.75
+        return abs(lhs.center.y - rhs.center.y) <= tolerance
+    }
+
+    private func horizontalFocusXSort(
+        from current: HorizontalKeyboardFocusNode,
+        forward: Bool
+    ) -> (HorizontalKeyboardFocusNode, HorizontalKeyboardFocusNode) -> Bool {
+        { lhs, rhs in
+            let lhsPrimary = abs(lhs.center.x - current.center.x)
+            let rhsPrimary = abs(rhs.center.x - current.center.x)
+            if abs(lhsPrimary - rhsPrimary) > 0.5 {
+                return lhsPrimary < rhsPrimary
+            }
+
+            let lhsSecondary = abs(lhs.center.y - current.center.y)
+            let rhsSecondary = abs(rhs.center.y - current.center.y)
+            if abs(lhsSecondary - rhsSecondary) > 0.5 {
+                return lhsSecondary < rhsSecondary
+            }
+
+            return forward ? lhs.order < rhs.order : lhs.order > rhs.order
+        }
+    }
+
+    private func horizontalFocusXWrapSort(
+        from current: HorizontalKeyboardFocusNode,
+        forward: Bool
+    ) -> (HorizontalKeyboardFocusNode, HorizontalKeyboardFocusNode) -> Bool {
+        { lhs, rhs in
+            if abs(lhs.center.x - rhs.center.x) > 0.5 {
+                return forward ? lhs.center.x < rhs.center.x : lhs.center.x > rhs.center.x
+            }
+
+            let lhsSecondary = abs(lhs.center.y - current.center.y)
+            let rhsSecondary = abs(rhs.center.y - current.center.y)
+            if abs(lhsSecondary - rhsSecondary) > 0.5 {
+                return lhsSecondary < rhsSecondary
+            }
+
+            return forward ? lhs.order < rhs.order : lhs.order > rhs.order
+        }
+    }
+
+    private func horizontalFocusYSort(
+        from current: HorizontalKeyboardFocusNode,
+        upward: Bool
+    ) -> (HorizontalKeyboardFocusNode, HorizontalKeyboardFocusNode) -> Bool {
+        { lhs, rhs in
+            let lhsPrimary = abs(lhs.center.y - current.center.y)
+            let rhsPrimary = abs(rhs.center.y - current.center.y)
+            if abs(lhsPrimary - rhsPrimary) > 0.5 {
+                return lhsPrimary < rhsPrimary
+            }
+
+            let lhsSecondary = abs(lhs.center.x - current.center.x)
+            let rhsSecondary = abs(rhs.center.x - current.center.x)
+            if abs(lhsSecondary - rhsSecondary) > 0.5 {
+                return lhsSecondary < rhsSecondary
+            }
+
+            return upward ? lhs.order < rhs.order : lhs.order > rhs.order
+        }
+    }
+
+    private func horizontalFocusYWrapSort(
+        from current: HorizontalKeyboardFocusNode,
+        upward: Bool
+    ) -> (HorizontalKeyboardFocusNode, HorizontalKeyboardFocusNode) -> Bool {
+        { lhs, rhs in
+            if abs(lhs.center.y - rhs.center.y) > 0.5 {
+                return upward ? lhs.center.y < rhs.center.y : lhs.center.y > rhs.center.y
+            }
+
+            let lhsSecondary = abs(lhs.center.x - current.center.x)
+            let rhsSecondary = abs(rhs.center.x - current.center.x)
+            if abs(lhsSecondary - rhsSecondary) > 0.5 {
+                return lhsSecondary < rhsSecondary
+            }
+
+            return upward ? lhs.order < rhs.order : lhs.order > rhs.order
+        }
+    }
+
+    private func focusHorizontalKeyboardNode(
+        _ node: HorizontalKeyboardFocusNode,
+        direction _: QuickSwitchKeyboardDirection
+    ) {
+        switch node.kind {
+        case .app:
+            keyboardFocusedAppGroupIndex = node.appGroupIndex
+            keyboardFocusedWindowID = nil
+            clearKeyboardBoundaryFeedback()
+            ensureAppShelfItemVisible(node.appGroupIndex)
+            _ = selectHorizontalMasonryDefaultWindowForApp(
+                node.appGroupIndex,
+                recordsSelectionChange: true
+            )
+            hoverAppGroup(node.appGroupIndex, source: .keyboard)
+        case .window:
+            guard let windowIndex = node.windowIndex,
+                  let windowID = node.windowID
+            else {
+                selectionChangedByLastCommand = false
+                return
+            }
+
+            let previousSelection = effectiveSelection
+            let next = QuickSwitchSelection(
+                appGroupIndex: node.appGroupIndex,
+                windowIndex: windowIndex,
+                windowID: windowID
+            )
+            keyboardFocusedAppGroupIndex = node.appGroupIndex
+            keyboardFocusedWindowID = windowID
+            currentSelection = next
+            columnSelectionHistory[next.appGroupIndex] = next.windowIndex
+            selectionChangedByLastCommand = previousSelection != next
+            clearKeyboardBoundaryFeedback()
+            ensureAppShelfItemVisible(node.appGroupIndex)
+            setHoverTarget(
+                .window(appGroupIndex: node.appGroupIndex, windowID: windowID, spaceID: node.spaceID),
+                source: .keyboard
+            )
+            ensureCurrentSelectionVisible(horizontalIntent: .alignWithAppShelf(animated: true))
+        }
+
+        needsLayout = true
+    }
+
+    private func nextHorizontalMasonrySelection(
+        from current: QuickSwitchSelection,
+        direction: QuickSwitchKeyboardDirection
+    ) -> QuickSwitchSelection? {
+        layoutSubtreeIfNeeded()
+
+        let cards = horizontalMasonryCardsInPlacementOrder()
+        guard let currentIndex = cards.firstIndex(where: { $0.item.window.id == current.windowID }) else {
+            return cards.first.map(selectionForCard)
+        }
+
+        switch direction {
+        case .right:
+            return selectionForCard(cards[(currentIndex + 1) % cards.count])
+        case .left:
+            return selectionForCard(cards[(currentIndex - 1 + cards.count) % cards.count])
+        case .up:
+            return nearestHorizontalMasonrySelection(from: cards[currentIndex], direction: .up)
+                ?? selectionForCard(cards.first ?? cards[currentIndex])
+        case .down:
+            return nearestHorizontalMasonrySelection(from: cards[currentIndex], direction: .down)
+                ?? selectionForCard(cards.last ?? cards[currentIndex])
+        }
+    }
+
+    private func nearestHorizontalMasonrySelection(
+        from currentCard: WaterfallCardLayers,
+        direction: QuickSwitchKeyboardDirection
+    ) -> QuickSwitchSelection? {
+        let currentFrame = currentCard.containerLayer.frame
+        let candidates = horizontalMasonryCardsInPlacementOrder().filter { card in
+            guard card.item.window.id != currentCard.item.window.id else { return false }
+            switch direction {
+            case .up:
+                return card.containerLayer.frame.minY >= currentFrame.maxY - 0.5
+            case .down:
+                return card.containerLayer.frame.maxY <= currentFrame.minY + 0.5
+            case .left, .right:
+                return false
+            }
+        }
+
+        let best = candidates.min { lhs, rhs in
+            let lhsFrame = lhs.containerLayer.frame
+            let rhsFrame = rhs.containerLayer.frame
+            let lhsPrimaryDistance = direction == .up
+                ? lhsFrame.minY - currentFrame.maxY
+                : currentFrame.minY - lhsFrame.maxY
+            let rhsPrimaryDistance = direction == .up
+                ? rhsFrame.minY - currentFrame.maxY
+                : currentFrame.minY - rhsFrame.maxY
+            if abs(lhsPrimaryDistance - rhsPrimaryDistance) > 0.5 {
+                return lhsPrimaryDistance < rhsPrimaryDistance
+            }
+
+            let lhsHorizontalDistance = abs(lhsFrame.midX - currentFrame.midX)
+            let rhsHorizontalDistance = abs(rhsFrame.midX - currentFrame.midX)
+            if abs(lhsHorizontalDistance - rhsHorizontalDistance) > 0.5 {
+                return lhsHorizontalDistance < rhsHorizontalDistance
+            }
+
+            return lhs.item.globalIndex < rhs.item.globalIndex
+        }
+
+        return best.map(selectionForCard)
+    }
+
+    private func horizontalMasonryCardsInPlacementOrder() -> [WaterfallCardLayers] {
+        waterfallColumns
+            .sorted { $0.column.appGroupIndex < $1.column.appGroupIndex }
+            .flatMap { column in
+                column.cards.sorted { $0.item.windowIndex < $1.item.windowIndex }
+            }
+    }
+
+    private func selectionForCard(_ card: WaterfallCardLayers) -> QuickSwitchSelection {
+        QuickSwitchSelection(
+            appGroupIndex: card.item.appGroupIndex,
+            windowIndex: card.item.windowIndex,
+            windowID: card.item.window.id
+        )
     }
 
     private func commitCurrentSelection() {
@@ -1145,9 +3279,24 @@
         _ selection: QuickSwitchSelection,
         horizontalIntent: WaterfallHorizontalIntent = .reveal
     ) {
+        if isHorizontalMasonryMode {
+            switch horizontalIntent {
+            case .reveal:
+                ensureHorizontalMasonrySelectionVisible(selection, animated: false)
+            case .alignWithAppShelf(let animated):
+                ensureHorizontalMasonrySelectionVisible(selection, animated: animated)
+            }
+            return
+        }
+
         guard
             let column = waterfallColumns.first(where: { $0.column.appGroupIndex == selection.appGroupIndex })
         else {
+            return
+        }
+
+        if waterfallShouldKeepFilteredColumnsCentered {
+            ensureWaterfallCardVisibleVertically(selection)
             return
         }
 
@@ -1161,11 +3310,16 @@
     }
 
     private func ensureWaterfallCardVisibleVertically(_ selection: QuickSwitchSelection) {
+        guard !isHorizontalMasonryMode else {
+            ensureHorizontalMasonrySelectionVisible(selection, animated: false)
+            return
+        }
+
         let visibleHeight = max(
             1,
             waterfallLayer.bounds.height
                 - WaterfallMetrics.headerHeight
-                - WaterfallMetrics.columnPadding * 2
+                - WaterfallMetrics.columnVerticalPadding * 2
         )
         let cardStride = WaterfallMetrics.cardHeight + WaterfallMetrics.cardGap
         let cardStart = CGFloat(selection.windowIndex) * cardStride
@@ -1188,6 +3342,11 @@
     }
 
     private func alignWaterfallColumnWithAppShelfIcon(appGroupIndex: Int, animated: Bool) {
+        if isHorizontalMasonryMode {
+            ensureHorizontalMasonryAppVisible(appGroupIndex, animated: animated)
+            return
+        }
+
         guard
             let item = appShelfItems.first(where: { $0.item.appGroupIndex == appGroupIndex }),
             let column = waterfallColumns.first(where: { $0.column.appGroupIndex == appGroupIndex })
@@ -1214,6 +3373,11 @@
     }
 
     private func ensureWaterfallColumnVisible(_ appGroupIndex: Int) {
+        if isHorizontalMasonryMode {
+            ensureHorizontalMasonryAppVisible(appGroupIndex, animated: false)
+            return
+        }
+
         guard let column = waterfallColumns.first(where: { $0.column.appGroupIndex == appGroupIndex }) else {
             return
         }
@@ -1222,18 +3386,31 @@
     }
 
     private func ensureWaterfallColumnVisible(_ column: WaterfallColumnLayers) {
+        if isHorizontalMasonryMode {
+            ensureHorizontalMasonryAppVisible(column.column.appGroupIndex, animated: false)
+            return
+        }
+
         waterfallScrollOffset = clampedWaterfallOffset(
             scrollOffset(
                 makingVisible: column.containerLayer.frame,
                 currentOffset: waterfallScrollOffset,
                 visibleWidth: waterfallLayer.bounds.width,
                 maxOffset: waterfallMaxScrollOffset,
-                inset: WaterfallMetrics.revealPadding
+                inset: WaterfallMetrics.horizontalRevealPadding
             )
         )
     }
 
     private var waterfallAlignmentScrollRange: ClosedRange<CGFloat> {
+        if isHorizontalMasonryMode {
+            return 0...0
+        }
+
+        if waterfallShouldKeepFilteredColumnsCentered {
+            return 0...0
+        }
+
         var minimumOffset: CGFloat = 0
         var maximumOffset = waterfallMaxScrollOffset
 
@@ -1258,6 +3435,10 @@
     private func clampedWaterfallAlignmentOffset(_ offset: CGFloat) -> CGFloat {
         let range = waterfallAlignmentScrollRange
         return min(max(range.lowerBound, offset), range.upperBound)
+    }
+
+    private var waterfallShouldKeepFilteredColumnsCentered: Bool {
+        currentViewModel?.lockedSpaceID != nil && waterfallMaxScrollOffset <= 0.5
     }
 
     private func setWaterfallScrollOffset(_ offset: CGFloat, animated: Bool) {
@@ -1292,6 +3473,80 @@
         animation.timingFunction = CAMediaTimingFunction(name: WaterfallAlignmentMetrics.animationTimingName)
         animation.isRemovedOnCompletion = true
         waterfallContentLayer.add(animation, forKey: "waterfallColumnAlignment")
+    }
+
+    private func ensureHorizontalMasonrySelectionVisible(
+        _ selection: QuickSwitchSelection,
+        animated: Bool
+    ) {
+        guard let card = waterfallCard(
+            appGroupIndex: selection.appGroupIndex,
+            windowIndex: selection.windowIndex
+        ) else {
+            return
+        }
+
+        let visibleFrame = card.containerLayer.frame.offsetBy(
+            dx: 0,
+            dy: waterfallContentLayer.frame.minY
+        )
+        let visibleHeight = waterfallLayer.bounds.height
+        let padding = WaterfallMetrics.revealPadding
+        var nextOffset = horizontalMasonryScrollOffset
+
+        if visibleFrame.maxY > visibleHeight - padding {
+            nextOffset -= visibleFrame.maxY - (visibleHeight - padding)
+        } else if visibleFrame.minY < padding {
+            nextOffset += padding - visibleFrame.minY
+        }
+
+        setHorizontalMasonryScrollOffset(nextOffset, animated: animated)
+    }
+
+    private func ensureHorizontalMasonryAppVisible(_ appGroupIndex: Int, animated: Bool) {
+        guard let firstCard = waterfallColumns
+            .first(where: { $0.column.appGroupIndex == appGroupIndex })?
+            .cards
+            .sorted(by: { $0.item.windowIndex < $1.item.windowIndex })
+            .first
+        else {
+            return
+        }
+
+        let cardTopDistance = horizontalMasonryContentHeight - firstCard.containerLayer.frame.maxY
+        setHorizontalMasonryScrollOffset(
+            cardTopDistance - WaterfallMetrics.revealPadding,
+            animated: animated
+        )
+    }
+
+    private func setHorizontalMasonryScrollOffset(_ offset: CGFloat, animated: Bool) {
+        let nextOffset = clampedHorizontalMasonryOffset(offset)
+        let previousPositionY = waterfallContentLayer.presentation()?.position.y
+            ?? waterfallContentLayer.position.y
+
+        horizontalMasonryScrollOffset = nextOffset
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        waterfallContentLayer.frame = horizontalMasonryContentFrame()
+        CATransaction.commit()
+
+        let nextPositionY = waterfallContentLayer.position.y
+        guard animated,
+              !NSWorkspace.shared.accessibilityDisplayShouldReduceMotion,
+              abs(previousPositionY - nextPositionY) > 0.5
+        else {
+            waterfallContentLayer.removeAnimation(forKey: "horizontalMasonryAlignment")
+            return
+        }
+
+        let animation = CABasicAnimation(keyPath: "position.y")
+        animation.fromValue = previousPositionY
+        animation.toValue = nextPositionY
+        animation.duration = WaterfallAlignmentMetrics.animationDuration
+        animation.timingFunction = CAMediaTimingFunction(name: WaterfallAlignmentMetrics.animationTimingName)
+        animation.isRemovedOnCompletion = true
+        waterfallContentLayer.add(animation, forKey: "horizontalMasonryAlignment")
     }
 
     private func scrollOffset(
@@ -1368,7 +3623,7 @@
     }
 
     private func setupBackdropBlurView() {
-        backdropBlurView.material = .fullScreenUI
+        backdropBlurView.material = resolvedTheme == .dark ? .hudWindow : .fullScreenUI
         backdropBlurView.blendingMode = .behindWindow
         backdropBlurView.state = .active
         backdropBlurView.isEmphasized = false
@@ -1386,19 +3641,91 @@
         addSubview(layerHostView, positioned: .above, relativeTo: backdropBlurView)
     }
 
+    private func applyThemeToBackdrop() {
+        let palette = themePalette
+        backdropBlurView.material = resolvedTheme == .dark ? .hudWindow : .fullScreenUI
+        backgroundLayer.colors = palette.backgroundGradientColors.map(\.cgColor)
+        backgroundLayer.locations = resolvedTheme == .dark
+            ? [0, 0.44, 0.72, 1].map(NSNumber.init(value:))
+            : [0, 1].map(NSNumber.init(value:))
+        safeAreaFillLayer.backgroundColor = palette.safeAreaFill.cgColor
+
+        let showsDarkBackdrop = resolvedTheme == .dark
+        darkAmbientLeftLayer.isHidden = !showsDarkBackdrop
+        darkAmbientCenterLayer.isHidden = !showsDarkBackdrop
+        darkAmbientRightLayer.isHidden = !showsDarkBackdrop
+        darkVignetteLayer.isHidden = !showsDarkBackdrop
+        guard showsDarkBackdrop else { return }
+
+        darkAmbientLeftLayer.colors = [
+            NSColor(calibratedRed: 72 / 255, green: 56 / 255, blue: 145 / 255, alpha: 0.34).cgColor,
+            NSColor(calibratedRed: 20 / 255, green: 28 / 255, blue: 76 / 255, alpha: 0.17).cgColor,
+            NSColor.clear.cgColor
+        ]
+        darkAmbientCenterLayer.colors = [
+            NSColor(calibratedRed: 14 / 255, green: 92 / 255, blue: 130 / 255, alpha: 0.26).cgColor,
+            NSColor(calibratedRed: 12 / 255, green: 54 / 255, blue: 89 / 255, alpha: 0.16).cgColor,
+            NSColor.clear.cgColor
+        ]
+        darkAmbientRightLayer.colors = [
+            NSColor(calibratedRed: 4 / 255, green: 92 / 255, blue: 108 / 255, alpha: 0.20).cgColor,
+            NSColor(calibratedRed: 0 / 255, green: 44 / 255, blue: 54 / 255, alpha: 0.15).cgColor,
+            NSColor.clear.cgColor
+        ]
+        darkVignetteLayer.colors = [
+            NSColor.black.withAlphaComponent(0.48).cgColor,
+            NSColor.clear.cgColor,
+            NSColor.black.withAlphaComponent(0.28).cgColor
+        ]
+        darkVignetteLayer.locations = [0, 0.36, 1].map(NSNumber.init(value:))
+    }
+
+    private func layoutBackdropLayers() {
+        applyThemeToBackdrop()
+        guard resolvedTheme == .dark else { return }
+
+        let width = max(1, bounds.width)
+        let height = max(1, bounds.height)
+        darkAmbientLeftLayer.frame = CGRect(
+            x: -width * 0.18,
+            y: -height * 0.10,
+            width: width * 0.82,
+            height: height * 1.24
+        )
+        darkAmbientCenterLayer.frame = CGRect(
+            x: width * 0.24,
+            y: height * 0.10,
+            width: width * 0.52,
+            height: height * 0.74
+        )
+        darkAmbientRightLayer.frame = CGRect(
+            x: width * 0.50,
+            y: -height * 0.12,
+            width: width * 0.72,
+            height: height * 1.26
+        )
+        darkVignetteLayer.frame = bounds
+    }
+
     private func setupLayers() {
         guard let rootLayer = layerHostView.layer else { return }
 
         rootLayer.masksToBounds = true
-        backgroundLayer.colors = [
-            NSColor.windowBackgroundColor.withAlphaComponent(0.58).cgColor,
-            NSColor.controlBackgroundColor.withAlphaComponent(0.48).cgColor
-        ]
         backgroundLayer.startPoint = CGPoint(x: 0.5, y: 1.0)
         backgroundLayer.endPoint = CGPoint(x: 0.5, y: 0.0)
         rootLayer.addSublayer(backgroundLayer)
+        for ambientLayer in darkBackdropAmbientLayers {
+            ambientLayer.type = .radial
+            ambientLayer.startPoint = CGPoint(x: 0.5, y: 0.5)
+            ambientLayer.endPoint = CGPoint(x: 1.0, y: 1.0)
+            ambientLayer.isHidden = true
+            rootLayer.addSublayer(ambientLayer)
+        }
+        darkVignetteLayer.startPoint = CGPoint(x: 0.5, y: 1.0)
+        darkVignetteLayer.endPoint = CGPoint(x: 0.5, y: 0.0)
+        darkVignetteLayer.isHidden = true
+        rootLayer.addSublayer(darkVignetteLayer)
 
-        safeAreaFillLayer.backgroundColor = NSColor.black.cgColor
         rootLayer.addSublayer(safeAreaFillLayer)
 
         glassLayer.cornerRadius = 0
@@ -1408,8 +3735,8 @@
         glassLayer.shadowOpacity = 0
         rootLayer.addSublayer(glassLayer)
 
-        laneLayer.backgroundColor = NSColor.controlBackgroundColor.withAlphaComponent(0.68).cgColor
-        laneLayer.cornerRadius = 16
+        laneLayer.backgroundColor = NSColor.clear.cgColor
+        laneLayer.cornerRadius = 0
         laneLayer.masksToBounds = true
         glassLayer.addSublayer(laneLayer)
         laneLayer.addSublayer(spaceLaneContentLayer)
@@ -1427,6 +3754,46 @@
 
         closeConfirmationLayers.containerLayer.isHidden = true
         glassLayer.addSublayer(closeConfirmationLayers.containerLayer)
+
+        closeFeedbackLayer.isHidden = true
+        closeFeedbackLayer.opacity = 0
+        closeFeedbackLayer.cornerRadius = 11
+        closeFeedbackLayer.borderWidth = 1
+        closeFeedbackLayer.masksToBounds = false
+        closeFeedbackLayer.shadowColor = NSColor.black.cgColor
+        closeFeedbackLayer.shadowOpacity = 0.14
+        closeFeedbackLayer.shadowRadius = 16
+        closeFeedbackLayer.shadowOffset = CGSize(width: 0, height: -5)
+        closeFeedbackLayer.zPosition = 190
+        closeFeedbackTextLayer.contentsScale = backingScaleFactor
+        closeFeedbackTextLayer.font = NSFont.systemFont(ofSize: 13, weight: .medium)
+        closeFeedbackTextLayer.fontSize = 13
+        closeFeedbackTextLayer.alignmentMode = .center
+        closeFeedbackTextLayer.truncationMode = .end
+        closeFeedbackLayer.addSublayer(closeFeedbackTextLayer)
+        glassLayer.addSublayer(closeFeedbackLayer)
+
+        viewModeToggleButtonLayer.cornerRadius = 10
+        viewModeToggleButtonLayer.masksToBounds = false
+        viewModeToggleButtonLayer.borderWidth = 1
+        viewModeToggleButtonLayer.shadowColor = NSColor.black.cgColor
+        viewModeToggleButtonLayer.shadowOffset = CGSize(width: 0, height: -2)
+        viewModeToggleButtonLayer.zPosition = 170
+        viewModeToggleIconLayer.contentsScale = backingScaleFactor
+        viewModeToggleButtonLayer.addSublayer(viewModeToggleIconLayer)
+        glassLayer.addSublayer(viewModeToggleButtonLayer)
+
+        themeToggleButtonLayer.cornerRadius = 10
+        themeToggleButtonLayer.masksToBounds = false
+        themeToggleButtonLayer.borderWidth = 1
+        themeToggleButtonLayer.shadowColor = NSColor.black.cgColor
+        themeToggleButtonLayer.shadowOffset = CGSize(width: 0, height: -2)
+        themeToggleButtonLayer.zPosition = 170
+        themeToggleIconLayer.contentsScale = backingScaleFactor
+        themeToggleButtonLayer.addSublayer(themeToggleIconLayer)
+        glassLayer.addSublayer(themeToggleButtonLayer)
+
+        applyThemeToBackdrop()
     }
 
     private func rebuildAppShelfItems() {
@@ -1434,22 +3801,15 @@
             item.containerLayer.removeFromSuperlayer()
         }
 
-        let selectedAppGroupIndex = effectiveSelection?.appGroupIndex
-        appShelfItems = (currentViewModel?.appShelf ?? []).map { item in
+        appShelfItems = (currentViewModel?.appShelf ?? []).enumerated().map { ordinal, item in
             let container = CALayer()
             container.name = item.app.name
 
             let background = CALayer()
             background.cornerRadius = 10
-            background.backgroundColor = (item.appGroupIndex == selectedAppGroupIndex
-                ? NSColor.systemFill.withAlphaComponent(0.16)
-                : NSColor.clear
-            ).cgColor
-            background.borderColor = (item.appGroupIndex == selectedAppGroupIndex
-                ? NSColor.separatorColor.withAlphaComponent(0.36)
-                : NSColor.clear
-            ).cgColor
-            background.borderWidth = item.appGroupIndex == selectedAppGroupIndex ? 1 : 0
+            background.backgroundColor = NSColor.clear.cgColor
+            background.borderColor = NSColor.clear.cgColor
+            background.borderWidth = 0
 
             let icon = CALayer()
             icon.contentsGravity = .resizeAspect
@@ -1458,11 +3818,23 @@
             icon.cornerRadius = 12
             icon.masksToBounds = false
 
+            let indexLabel = makeTextLayer(
+                string: appShelfIndexText(forOrdinal: ordinal),
+                fontSize: AppShelfMetrics.indexFontSize,
+                weight: .regular,
+                color: appShelfIndexColor,
+                alignment: .center
+            )
+            indexLabel.font = appShelfIndexFont(size: AppShelfMetrics.indexFontSize)
+            indexLabel.fontSize = AppShelfMetrics.indexFontSize
+            indexLabel.truncationMode = .end
+            indexLabel.zPosition = 14
+
             let label = makeTextLayer(
                 string: item.app.name,
                 fontSize: 11,
                 weight: .regular,
-                color: .secondaryLabelColor,
+                color: themePalette.appShelfLabelText,
                 alignment: .center
             )
 
@@ -1482,6 +3854,7 @@
             let closeButton = makeCloseButtonLayers()
 
             container.addSublayer(background)
+            container.addSublayer(indexLabel)
             container.addSublayer(icon)
             container.addSublayer(label)
             container.addSublayer(badge)
@@ -1492,6 +3865,7 @@
                 item: item,
                 containerLayer: container,
                 backgroundLayer: background,
+                indexLayer: indexLabel,
                 iconLayer: icon,
                 labelLayer: label,
                 badgeLayer: badge,
@@ -1512,27 +3886,37 @@
             container.name = column.app.name
             container.cornerRadius = 14
             container.masksToBounds = true
-            container.backgroundColor = NSColor.controlBackgroundColor.withAlphaComponent(0.56).cgColor
-            container.borderColor = NSColor.separatorColor.withAlphaComponent(0.34).cgColor
+            container.backgroundColor = themePalette.columnBackground.cgColor
+            container.borderColor = themePalette.columnBorder.cgColor
             container.borderWidth = 1
 
+            let cardsClip = CALayer()
+            cardsClip.masksToBounds = true
+            cardsClip.backgroundColor = NSColor.clear.cgColor
+
             let header = CALayer()
-            header.backgroundColor = NSColor.controlBackgroundColor.withAlphaComponent(0.68).cgColor
+            header.backgroundColor = themePalette.columnHeaderBackground.cgColor
+            header.zPosition = 40
 
             let appName = makeTextLayer(
                 string: column.app.name,
                 fontSize: 13,
                 weight: .semibold,
-                color: .labelColor
+                color: themePalette.columnText,
+                alignment: .center
             )
             let count = makeTextLayer(
                 string: "\(column.windows.count)",
                 fontSize: 11,
                 weight: .medium,
-                color: .secondaryLabelColor,
+                color: themePalette.columnSecondaryText,
                 alignment: .right
             )
 
+            appName.zPosition = 42
+            count.zPosition = 42
+
+            container.addSublayer(cardsClip)
             container.addSublayer(header)
             container.addSublayer(appName)
             container.addSublayer(count)
@@ -1557,14 +3941,15 @@
                     string: window.window.title.isEmpty ? "Untitled Window" : window.window.title,
                     fontSize: 12,
                     weight: .medium,
-                    color: .labelColor
+                    color: themePalette.cardText
                 )
                 title.truncationMode = .middle
                 let meta = makeTextLayer(
                     string: waterfallMetaText(for: window),
                     fontSize: 10,
                     weight: .regular,
-                    color: .secondaryLabelColor
+                    color: themePalette.cardSecondaryText,
+                    alignment: .right
                 )
                 let appIcon = CALayer()
                 appIcon.contentsGravity = .resizeAspect
@@ -1577,13 +3962,13 @@
                     string: waterfallStateText(for: window),
                     fontSize: 10,
                     weight: .medium,
-                    color: .secondaryLabelColor,
+                    color: themePalette.cardSecondaryText,
                     alignment: .right
                 )
                 let shine = CAGradientLayer()
                 shine.colors = [
                     NSColor.white.withAlphaComponent(0.00).cgColor,
-                    NSColor.white.withAlphaComponent(0.16).cgColor,
+                    themePalette.shinePeak.cgColor,
                     NSColor.white.withAlphaComponent(0.00).cgColor
                 ]
                 shine.startPoint = CGPoint(x: 0, y: 1)
@@ -1599,7 +3984,7 @@
                 card.addSublayer(state)
                 card.addSublayer(shine)
                 card.addSublayer(closeButton.containerLayer)
-                container.addSublayer(card)
+                cardsClip.addSublayer(card)
 
                 return WaterfallCardLayers(
                     item: window,
@@ -1620,6 +4005,7 @@
             return WaterfallColumnLayers(
                 column: column,
                 containerLayer: container,
+                cardsClipLayer: cardsClip,
                 headerLayer: header,
                 appNameLayer: appName,
                 countLayer: count,
@@ -1632,66 +4018,108 @@
     }
 
     private func rebuildSpaceLaneSegments() {
-        for segment in spaceLaneSegments {
-            segment.containerLayer.removeFromSuperlayer()
+        for group in spaceLaneDisplayGroups {
+            group.containerLayer.removeFromSuperlayer()
         }
 
-        let spaces = currentViewModel?.displays.flatMap(\.spaces) ?? []
-        spaceLaneSegments = spaces.map { space in
-            let container = CALayer()
-            container.name = space.label
-            container.cornerRadius = 10
-            container.borderWidth = 1
-            container.borderColor = NSColor.separatorColor.withAlphaComponent(0.34).cgColor
-            container.backgroundColor = spaceColor(for: space).cgColor
-            container.shadowColor = NSColor.black.cgColor
+        var groups: [SpaceLaneDisplayGroupLayers] = []
+        var allSegments: [SpaceLaneSegmentLayers] = []
 
-            let labelLayer = makeTextLayer(
-                string: space.label,
-                fontSize: 15,
-                weight: .semibold,
-                color: .labelColor
-            )
-            let countLayer = makeTextLayer(
-                string: "\(space.windowCount)",
-                fontSize: 12,
-                weight: .medium,
-                color: .secondaryLabelColor,
-                alignment: .center
-            )
-            let appLayer = makeTextLayer(
-                string: appIdentifierText(for: space),
-                fontSize: 12,
-                weight: space.type == .fullscreen ? .medium : .regular,
-                color: space.type == .fullscreen ? .labelColor : .secondaryLabelColor,
-                alignment: space.type == .fullscreen ? .center : .left
-            )
-            let windowBlocks = space.type == .fullscreen
-                ? []
-                : makeWindowBlocks(count: min(space.windowCount, 5), space: space)
-            let fullscreenMarkerLayer = makeFullscreenMarkerLayer(for: space)
+        for display in currentViewModel?.displays ?? [] {
+            let groupContainer = CALayer()
+            groupContainer.name = display.displayLabel
+            groupContainer.cornerRadius = 14
+            groupContainer.masksToBounds = false
+            groupContainer.borderWidth = 0
+            groupContainer.borderColor = NSColor.clear.cgColor
+            groupContainer.backgroundColor = themePalette.displayGroupBackground.cgColor
+            groupContainer.shadowColor = NSColor.black.cgColor
+            groupContainer.shadowOpacity = 0
+            groupContainer.shadowRadius = 0
+            groupContainer.shadowOffset = .zero
 
-            container.addSublayer(labelLayer)
-            container.addSublayer(countLayer)
-            container.addSublayer(appLayer)
-            if let fullscreenMarkerLayer {
-                container.addSublayer(fullscreenMarkerLayer)
+            let segments = display.spaces.map { space in
+                let container = CAGradientLayer()
+                container.name = space.label
+                container.cornerRadius = 10
+                container.borderWidth = 1
+                container.borderColor = NSColor.separatorColor.withAlphaComponent(0.34).cgColor
+                container.backgroundColor = NSColor.clear.cgColor
+                container.startPoint = CGPoint(x: 0.5, y: 1.0)
+                container.endPoint = CGPoint(x: 0.5, y: 0.0)
+                container.shadowColor = NSColor.black.cgColor
+
+                let labelLayer = makeTextLayer(
+                    string: space.label,
+                    fontSize: 15,
+                    weight: .semibold,
+                    color: themePalette.spaceLanePrimaryText
+                )
+                let countLayer = makeTextLayer(
+                    string: "\(space.windowCount)",
+                    fontSize: 12,
+                    weight: .medium,
+                    color: themePalette.spaceLaneSecondaryText,
+                    alignment: .center
+                )
+                let appLayer = makeTextLayer(
+                    string: appIdentifierText(for: space),
+                    fontSize: 12,
+                    weight: space.type == .fullscreen ? .medium : .regular,
+                    color: space.type == .fullscreen ? themePalette.spaceLanePrimaryText : themePalette.spaceLaneSecondaryText,
+                    alignment: space.type == .fullscreen ? .center : .left
+                )
+                let splitAppLayers = splitViewAppNames(for: space).map { name in
+                    makeTextLayer(
+                        string: name,
+                        fontSize: 12,
+                        weight: .medium,
+                        color: themePalette.spaceLanePrimaryText,
+                        alignment: .center
+                    )
+                }
+                let windowBlocks = space.type == .fullscreen
+                    ? []
+                    : makeWindowBlocks(count: min(space.windowCount, 5), space: space)
+                let fullscreenMarkerLayer = makeFullscreenMarkerLayer(for: space)
+
+                container.addSublayer(labelLayer)
+                container.addSublayer(countLayer)
+                container.addSublayer(appLayer)
+                if let fullscreenMarkerLayer {
+                    container.addSublayer(fullscreenMarkerLayer)
+                }
+                for splitAppLayer in splitAppLayers {
+                    container.addSublayer(splitAppLayer)
+                }
+                for block in windowBlocks {
+                    container.addSublayer(block)
+                }
+                groupContainer.addSublayer(container)
+
+                return SpaceLaneSegmentLayers(
+                    space: space,
+                    containerLayer: container,
+                    labelLayer: labelLayer,
+                    countLayer: countLayer,
+                    appLayer: appLayer,
+                    splitAppLayers: splitAppLayers,
+                    windowBlocks: windowBlocks,
+                    fullscreenMarkerLayer: fullscreenMarkerLayer
+                )
             }
-            for block in windowBlocks {
-                container.addSublayer(block)
-            }
-            spaceLaneContentLayer.addSublayer(container)
 
-            return SpaceLaneSegmentLayers(
-                space: space,
-                containerLayer: container,
-                labelLayer: labelLayer,
-                countLayer: countLayer,
-                appLayer: appLayer,
-                windowBlocks: windowBlocks,
-                fullscreenMarkerLayer: fullscreenMarkerLayer
-            )
+            spaceLaneContentLayer.addSublayer(groupContainer)
+            groups.append(SpaceLaneDisplayGroupLayers(
+                display: display,
+                containerLayer: groupContainer,
+                segments: segments
+            ))
+            allSegments.append(contentsOf: segments)
         }
+
+        spaceLaneDisplayGroups = groups
+        spaceLaneSegments = allSegments
     }
 
     private func layoutLayers() {
@@ -1699,6 +4127,7 @@
         CATransaction.setDisableActions(true)
 
         backgroundLayer.frame = bounds
+        layoutBackdropLayers()
 
         let safeAreaTopInset = topSafeAreaInset
         safeAreaFillLayer.frame = CGRect(
@@ -1740,8 +4169,283 @@
         layoutAppShelfItems()
         layoutWaterfallColumns()
         layoutCloseConfirmation()
+        layoutCloseFeedback()
+        layoutViewModeToggleButton()
+        layoutThemeToggleButton()
 
         CATransaction.commit()
+    }
+
+    private func layoutViewModeToggleButton() {
+        let size = ViewModeToggleMetrics.visualSize
+        let topMargin = topSafeAreaInset + RootLayoutMetrics.topContentMargin
+        let x = max(
+            RootLayoutMetrics.horizontalMargin,
+            glassLayer.bounds.width - RootLayoutMetrics.horizontalMargin - size
+        )
+        let y = max(
+            RootLayoutMetrics.bottomMargin,
+            glassLayer.bounds.height - topMargin - size
+        )
+        viewModeToggleButtonLayer.frame = CGRect(x: x, y: y, width: size, height: size)
+        viewModeToggleButtonLayer.cornerRadius = ViewModeToggleMetrics.cornerRadius
+        let visualState = viewModeToggleVisualState
+        let isSelectedState = viewModeToggleVisualStateIsSelected(visualState)
+        viewModeToggleButtonLayer.backgroundColor = (isSelectedState
+            ? viewModeToggleBlueColor
+            : toggleIdleBackgroundColor(hovered: isViewModeToggleButtonHovered)
+        ).cgColor
+        viewModeToggleButtonLayer.borderColor = (isSelectedState
+            ? viewModeToggleBlueColor.withAlphaComponent(0.96)
+            : viewModeToggleBlueColor.withAlphaComponent(isViewModeToggleButtonHovered ? 0.72 : 0.34)
+        ).cgColor
+        viewModeToggleButtonLayer.shadowOpacity = isSelectedState ? 0.16 : (isViewModeToggleButtonHovered ? 0.11 : 0.06)
+        viewModeToggleButtonLayer.shadowRadius = isSelectedState
+            ? ViewModeToggleMetrics.selectedShadowRadius
+            : ViewModeToggleMetrics.idleShadowRadius
+        viewModeToggleIconLayer.contentsScale = backingScaleFactor
+        let iconInset = ViewModeToggleMetrics.iconInset
+        viewModeToggleIconLayer.frame = viewModeToggleButtonLayer.bounds.insetBy(dx: iconInset, dy: iconInset)
+        layoutViewModeToggleIcon()
+    }
+
+    private func layoutThemeToggleButton() {
+        let size = ViewModeToggleMetrics.visualSize
+        let topMargin = topSafeAreaInset + RootLayoutMetrics.topContentMargin
+        let viewModeFrame = viewModeToggleButtonLayer.frame
+        let fallbackX = max(
+            RootLayoutMetrics.horizontalMargin,
+            glassLayer.bounds.width - RootLayoutMetrics.horizontalMargin - size * 2 - ThemeToggleMetrics.buttonGap
+        )
+        let x = max(
+            RootLayoutMetrics.horizontalMargin,
+            (viewModeFrame.width > 0 ? viewModeFrame.minX : fallbackX + size + ThemeToggleMetrics.buttonGap)
+                - ThemeToggleMetrics.buttonGap
+                - size
+        )
+        let y = max(
+            RootLayoutMetrics.bottomMargin,
+            glassLayer.bounds.height - topMargin - size
+        )
+        themeToggleButtonLayer.frame = CGRect(x: x, y: y, width: size, height: size)
+        themeToggleButtonLayer.cornerRadius = ViewModeToggleMetrics.cornerRadius
+        let isSelectedState = resolvedTheme == .dark
+        themeToggleButtonLayer.backgroundColor = (isSelectedState
+            ? viewModeToggleBlueColor
+            : themeToggleIdleBackgroundColor
+        ).cgColor
+        themeToggleButtonLayer.borderColor = (isSelectedState
+            ? viewModeToggleBlueColor.withAlphaComponent(0.96)
+            : viewModeToggleBlueColor.withAlphaComponent(isThemeToggleButtonHovered ? 0.72 : 0.34)
+        ).cgColor
+        themeToggleButtonLayer.shadowOpacity = isSelectedState ? 0.18 : (isThemeToggleButtonHovered ? 0.12 : 0.06)
+        themeToggleButtonLayer.shadowRadius = isSelectedState
+            ? ViewModeToggleMetrics.selectedShadowRadius
+            : ViewModeToggleMetrics.idleShadowRadius
+        themeToggleIconLayer.contentsScale = backingScaleFactor
+        let iconInset = ViewModeToggleMetrics.iconInset
+        themeToggleIconLayer.frame = themeToggleButtonLayer.bounds.insetBy(dx: iconInset, dy: iconInset)
+        layoutThemeToggleIcon()
+    }
+
+    private func layoutViewModeToggleIcon() {
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        viewModeToggleIconLayer.sublayers?.forEach { $0.removeFromSuperlayer() }
+
+        let bounds = viewModeToggleIconLayer.bounds
+        guard bounds.width > 0, bounds.height > 0 else {
+            CATransaction.commit()
+            return
+        }
+
+        let visualState = viewModeToggleVisualState
+        let isSelectedState = viewModeToggleVisualStateIsSelected(visualState)
+        let strokeColor = isSelectedState
+            ? NSColor.white.withAlphaComponent(0.98)
+            : viewModeToggleBlueColor.withAlphaComponent(0.96)
+        let fillColor = isSelectedState
+            ? NSColor.white.withAlphaComponent(0.22)
+            : viewModeToggleBlueColor.withAlphaComponent(0.06)
+        let glyphRect = centeredSquare(in: bounds)
+
+        switch visualState {
+        case .verticalAvailable, .verticalSelected:
+            addVerticalColumnsToggleGlyph(
+                in: glyphRect,
+                strokeColor: strokeColor,
+                fillColor: fillColor
+            )
+        case .horizontalAvailable, .horizontalSelected:
+            addHorizontalMasonryToggleGlyph(
+                in: glyphRect,
+                strokeColor: strokeColor,
+                fillColor: fillColor
+            )
+        }
+
+        CATransaction.commit()
+    }
+
+    private func layoutThemeToggleIcon() {
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        themeToggleIconLayer.sublayers?.forEach { $0.removeFromSuperlayer() }
+
+        let bounds = themeToggleIconLayer.bounds
+        guard bounds.width > 0, bounds.height > 0 else {
+            CATransaction.commit()
+            return
+        }
+
+        let isSelectedState = resolvedTheme == .dark
+        let strokeColor = isSelectedState
+            ? NSColor.white.withAlphaComponent(0.98)
+            : viewModeToggleBlueColor.withAlphaComponent(0.96)
+        let lightFillColor = isSelectedState
+            ? NSColor.white.withAlphaComponent(0.22)
+            : viewModeToggleBlueColor.withAlphaComponent(0.06)
+        let darkFillColor = isSelectedState
+            ? NSColor.white.withAlphaComponent(0.96)
+            : viewModeToggleBlueColor.withAlphaComponent(0.82)
+        let glyphRect = centeredSquare(in: bounds).insetBy(dx: 0.75, dy: 0.75)
+        addThemeToggleHalfDiskGlyph(
+            in: glyphRect,
+            strokeColor: strokeColor,
+            lightFillColor: lightFillColor,
+            darkFillColor: darkFillColor
+        )
+
+        CATransaction.commit()
+    }
+
+    private func addThemeToggleHalfDiskGlyph(
+        in rect: CGRect,
+        strokeColor: NSColor,
+        lightFillColor: NSColor,
+        darkFillColor: NSColor
+    ) {
+        let circlePath = CGPath(
+            ellipseIn: rect,
+            transform: nil
+        )
+        let baseLayer = CAShapeLayer()
+        baseLayer.contentsScale = backingScaleFactor
+        baseLayer.frame = themeToggleIconLayer.bounds
+        baseLayer.path = circlePath
+        baseLayer.fillColor = lightFillColor.cgColor
+        baseLayer.strokeColor = NSColor.clear.cgColor
+        themeToggleIconLayer.addSublayer(baseLayer)
+
+        let radius = min(rect.width, rect.height) / 2
+        let center = CGPoint(x: rect.midX, y: rect.midY)
+        let halfPath = CGMutablePath()
+        halfPath.move(to: CGPoint(x: center.x, y: center.y + radius))
+        halfPath.addArc(
+            center: center,
+            radius: radius,
+            startAngle: .pi / 2,
+            endAngle: .pi * 1.5,
+            clockwise: false
+        )
+        halfPath.closeSubpath()
+
+        let halfLayer = CAShapeLayer()
+        halfLayer.contentsScale = backingScaleFactor
+        halfLayer.frame = themeToggleIconLayer.bounds
+        halfLayer.path = halfPath
+        halfLayer.fillColor = darkFillColor.cgColor
+        halfLayer.strokeColor = NSColor.clear.cgColor
+        themeToggleIconLayer.addSublayer(halfLayer)
+
+        let outlineLayer = CAShapeLayer()
+        outlineLayer.contentsScale = backingScaleFactor
+        outlineLayer.frame = themeToggleIconLayer.bounds
+        outlineLayer.path = circlePath
+        outlineLayer.fillColor = NSColor.clear.cgColor
+        outlineLayer.strokeColor = strokeColor.cgColor
+        outlineLayer.lineWidth = ViewModeToggleMetrics.glyphLineWidth
+        outlineLayer.lineJoin = .round
+        themeToggleIconLayer.addSublayer(outlineLayer)
+    }
+
+    private func addVerticalColumnsToggleGlyph(
+        in rect: CGRect,
+        strokeColor: NSColor,
+        fillColor: NSColor
+    ) {
+        let columnWidth = rect.width * 0.22
+        let gap = (rect.width - columnWidth * 3) / 2
+        for index in 0..<3 {
+            let x = rect.minX + CGFloat(index) * (columnWidth + gap)
+            let columnRect = CGRect(x: x, y: rect.minY, width: columnWidth, height: rect.height)
+            addViewModeToggleRoundedRect(
+                columnRect,
+                cornerRadius: ViewModeToggleMetrics.glyphCornerRadius,
+                strokeColor: strokeColor,
+                fillColor: fillColor,
+                lineWidth: ViewModeToggleMetrics.glyphLineWidth
+            )
+        }
+    }
+
+    private func addHorizontalMasonryToggleGlyph(
+        in rect: CGRect,
+        strokeColor: NSColor,
+        fillColor: NSColor
+    ) {
+        let cellSize = rect.width * 0.38
+        let gap = rect.width - cellSize * 2
+        for row in 0..<2 {
+            for column in 0..<2 {
+                let cellRect = CGRect(
+                    x: rect.minX + CGFloat(column) * (cellSize + gap),
+                    y: rect.minY + CGFloat(row) * (cellSize + gap),
+                    width: cellSize,
+                    height: cellSize
+                )
+                addViewModeToggleRoundedRect(
+                    cellRect,
+                    cornerRadius: ViewModeToggleMetrics.glyphCornerRadius,
+                    strokeColor: strokeColor,
+                    fillColor: fillColor,
+                    lineWidth: ViewModeToggleMetrics.glyphLineWidth
+                )
+            }
+        }
+    }
+
+    private func addViewModeToggleRoundedRect(
+        _ rect: CGRect,
+        cornerRadius: CGFloat,
+        strokeColor: NSColor,
+        fillColor: NSColor,
+        lineWidth: CGFloat
+    ) {
+        let layer = CAShapeLayer()
+        layer.contentsScale = backingScaleFactor
+        layer.frame = viewModeToggleIconLayer.bounds
+        layer.path = CGPath(
+            roundedRect: rect,
+            cornerWidth: cornerRadius,
+            cornerHeight: cornerRadius,
+            transform: nil
+        )
+        layer.fillColor = fillColor.cgColor
+        layer.strokeColor = strokeColor.cgColor
+        layer.lineWidth = lineWidth
+        layer.lineJoin = .round
+        viewModeToggleIconLayer.addSublayer(layer)
+    }
+
+    private func centeredSquare(in rect: CGRect) -> CGRect {
+        let side = min(rect.width, rect.height)
+        return CGRect(
+            x: rect.midX - side / 2,
+            y: rect.midY - side / 2,
+            width: side,
+            height: side
+        )
     }
 
     private var topSafeAreaInset: CGFloat {
@@ -1823,15 +4527,34 @@
     }
 
     private func layoutSpaceLaneSegments() {
-        guard !spaceLaneSegments.isEmpty else { return }
+        guard !spaceLaneDisplayGroups.isEmpty, !spaceLaneSegments.isEmpty else { return }
 
-        let gap: CGFloat = 10
-        let segmentHeight = max(1, laneLayer.bounds.height - 20)
-        let availableWidth = laneLayer.bounds.width - 24 - CGFloat(spaceLaneSegments.count - 1) * gap
-        let segmentWidth = max(96, min(150, availableWidth / CGFloat(spaceLaneSegments.count)))
+        let groupOuterVerticalInset: CGFloat = 6
+        let groupHeight = max(1, laneLayer.bounds.height - groupOuterVerticalInset * 2)
+        let segmentHeight = max(1, groupHeight - SpaceLaneMetrics.groupVerticalPadding * 2)
+        let groupGapWidth = CGFloat(max(0, spaceLaneDisplayGroups.count - 1)) * SpaceLaneMetrics.groupGap
+        let segmentGapWidth = spaceLaneDisplayGroups.reduce(CGFloat(0)) { total, group in
+            total + CGFloat(max(0, group.segments.count - 1)) * SpaceLaneMetrics.segmentGap
+        }
+        let groupPaddingWidth = CGFloat(spaceLaneDisplayGroups.count) * SpaceLaneMetrics.groupHorizontalPadding * 2
+        let availableWidth = laneLayer.bounds.width
+            - SpaceLaneMetrics.horizontalPadding * 2
+            - groupGapWidth
+            - segmentGapWidth
+            - groupPaddingWidth
+        let segmentWidth = max(
+            SpaceLaneMetrics.segmentMinWidth,
+            min(SpaceLaneMetrics.segmentMaxWidth, availableWidth / CGFloat(spaceLaneSegments.count))
+        )
+        let groupWidths = spaceLaneDisplayGroups.map { group in
+            SpaceLaneMetrics.groupHorizontalPadding * 2
+                + CGFloat(group.segments.count) * segmentWidth
+                + CGFloat(max(0, group.segments.count - 1)) * SpaceLaneMetrics.segmentGap
+        }
+        let segmentGroupWidth = groupWidths.reduce(0, +) + groupGapWidth
         spaceLaneContentWidth = max(
             laneLayer.bounds.width,
-            24 + CGFloat(spaceLaneSegments.count) * segmentWidth + CGFloat(spaceLaneSegments.count - 1) * gap
+            SpaceLaneMetrics.horizontalPadding * 2 + segmentGroupWidth
         )
         spaceLaneScrollOffset = clampedSpaceLaneOffset(spaceLaneScrollOffset)
         spaceLaneContentLayer.frame = CGRect(
@@ -1841,13 +4564,35 @@
             height: laneLayer.bounds.height
         )
 
-        var x: CGFloat = 12
+        var x = max(
+            SpaceLaneMetrics.horizontalPadding,
+            (spaceLaneContentWidth - segmentGroupWidth) / 2
+        )
 
-        for segment in spaceLaneSegments {
-            segment.containerLayer.frame = CGRect(x: x, y: 10, width: segmentWidth, height: segmentHeight)
-            applySpaceLaneVisualState(segment)
-            layoutSpaceLaneSegmentContents(segment)
-            x += segmentWidth + gap
+        for (index, group) in spaceLaneDisplayGroups.enumerated() {
+            let groupWidth = groupWidths[index]
+            group.containerLayer.frame = CGRect(
+                x: x,
+                y: groupOuterVerticalInset,
+                width: groupWidth,
+                height: groupHeight
+            )
+            applySpaceLaneDisplayGroupVisualState(group)
+
+            var segmentX = SpaceLaneMetrics.groupHorizontalPadding
+            for segment in group.segments {
+                segment.containerLayer.frame = CGRect(
+                    x: segmentX,
+                    y: SpaceLaneMetrics.groupVerticalPadding,
+                    width: segmentWidth,
+                    height: segmentHeight
+                )
+                applySpaceLaneVisualState(segment)
+                layoutSpaceLaneSegmentContents(segment)
+                segmentX += segmentWidth + SpaceLaneMetrics.segmentGap
+            }
+
+            x += groupWidth + SpaceLaneMetrics.groupGap
         }
     }
 
@@ -1859,36 +4604,145 @@
         min(max(0, offset), spaceLaneMaxScrollOffset)
     }
 
-    private func applySpaceLaneVisualState(_ segment: SpaceLaneSegmentLayers) {
-        let isHovered = segment.space.id == hoveredSpaceID
-        let isFocused = segment.space.id == activeSpaceFocusID
-        let isCurrent = segment.space.isCurrent
-        let isActive = isHovered || isFocused
+    private func applySpaceLaneDisplayGroupVisualState(_ group: SpaceLaneDisplayGroupLayers) {
+        let hasActiveSegment = group.segments.contains { segment in
+            segment.space.id == activeSpaceFocusID
+                || appHoverAssociatedSpaceIDs.contains(segment.space.id)
+                || segment.space.id == windowHoverAssociatedSpaceID
+                || segment.space.id == currentViewModel?.lockedSpaceID
+        }
+        let hasCurrentSegment = group.display.spaces.contains { $0.isCurrent }
+        group.containerLayer.backgroundColor = themePalette.displayGroupBackground.cgColor
+        group.containerLayer.borderColor = NSColor.clear.cgColor
+        group.containerLayer.borderWidth = 0
+        group.containerLayer.shadowOpacity = 0
+        group.containerLayer.shadowRadius = 0
+        group.containerLayer.shadowOffset = .zero
+        group.containerLayer.zPosition = hasActiveSegment ? 8 : hasCurrentSegment ? 4 : 0
+        group.containerLayer.shadowPath = nil
+    }
 
-        segment.containerLayer.borderWidth = (isCurrent || isActive) ? 1.5 : 1
-        segment.containerLayer.borderColor = (isActive
-            ? NSColor.controlAccentColor.withAlphaComponent(0.54)
-            : isCurrent
-                ? NSColor.labelColor.withAlphaComponent(0.34)
-                : NSColor.separatorColor.withAlphaComponent(0.34)
+    private func applySpaceLaneVisualState(_ segment: SpaceLaneSegmentLayers) {
+        let isHovered = segment.space.id == activeSpaceFocusID
+        let isFocused = segment.space.id == activeSpaceFocusID
+        let isLocked = segment.space.id == currentViewModel?.lockedSpaceID
+        let isCurrent = segment.space.isCurrent
+        let hasWindows = segment.space.windowCount > 0
+        let isAppAssociated = appHoverAssociatedSpaceIDs.contains(segment.space.id)
+        let isWindowAssociated = segment.space.id == windowHoverAssociatedSpaceID
+        let isActive = isHovered || isFocused || isLocked
+        let isAssociated = (isAppAssociated || isWindowAssociated) && !isActive
+
+        segment.containerLayer.borderWidth = (hasWindows || isCurrent || isActive || isAssociated) ? 1.5 : 1
+        segment.containerLayer.borderColor = (isLocked
+            ? NSColor.white.withAlphaComponent(0.86)
+            : isActive
+            ? spaceLaneOccupiedColor.withAlphaComponent(isLocked ? 0.92 : 0.62)
+            : isAssociated
+                ? spaceLaneOccupiedColor.withAlphaComponent(0.50)
+                : hasWindows
+                    ? spaceLaneOccupiedColor.withAlphaComponent(isCurrent ? 0.54 : 0.44)
+                : isCurrent
+                    ? themePalette.spaceLanePrimaryText.withAlphaComponent(0.34)
+                : themePalette.columnBorder.withAlphaComponent(resolvedTheme == .dark ? 0.58 : 0.34)
         ).cgColor
-        segment.containerLayer.backgroundColor = (isActive
-            ? accentTintedWindowBackground(fraction: 0.10, alpha: 0.94)
-            : spaceColor(for: segment.space)
-        ).cgColor
-        segment.containerLayer.shadowOpacity = isActive ? 0.26 : isCurrent ? 0.14 : 0
-        segment.containerLayer.shadowRadius = isActive ? 24 : isCurrent ? 12 : 0
-        segment.containerLayer.shadowOffset = CGSize(width: 0, height: isActive ? -6 : isCurrent ? -2.5 : 0)
-        segment.containerLayer.zPosition = isActive ? 30 : isCurrent ? 10 : 0
-        segment.containerLayer.transform = isActive
-            ? CATransform3DMakeScale(1.03, 1.03, 1)
-            : CATransform3DIdentity
-        segment.containerLayer.shadowPath = CGPath(
-            roundedRect: segment.containerLayer.bounds,
-            cornerWidth: segment.containerLayer.cornerRadius,
-            cornerHeight: segment.containerLayer.cornerRadius,
-            transform: nil
+        if isLocked {
+            applySpaceLaneSolidFill(
+                to: segment.containerLayer,
+                color: spaceLaneLockedFillColor
+            )
+        } else if !hasWindows {
+            applySpaceLaneSolidFill(to: segment.containerLayer, color: .clear)
+        } else if isActive {
+            applySpaceLaneSolidFill(
+                to: segment.containerLayer,
+                color: accentTintedWindowBackground(fraction: 0.10, alpha: 0.94)
+            )
+        } else if isAssociated {
+            applySpaceLaneSolidFill(
+                to: segment.containerLayer,
+                color: accentTintedWindowBackground(fraction: 0.07, alpha: 0.90)
+            )
+        } else if hasWindows {
+            applySpaceLaneGradientFill(
+                to: segment.containerLayer,
+                colors: spaceLaneIdleOccupiedGradientColors()
+            )
+        }
+        segment.containerLayer.shadowColor = isLocked
+            ? NSColor.white.withAlphaComponent(0.98).cgColor
+            : NSColor.black.cgColor
+        segment.containerLayer.shadowOpacity = (hasWindows || isLocked)
+            ? (isLocked ? 0.72 : isActive ? 0.26 : isAssociated ? 0.18 : isCurrent ? 0.14 : 0)
+            : 0
+        segment.containerLayer.shadowRadius = (hasWindows || isLocked)
+            ? (isLocked ? 30 : isActive ? 24 : isAssociated ? 18 : isCurrent ? 12 : 0)
+            : 0
+        segment.containerLayer.shadowOffset = CGSize(
+            width: 0,
+            height: (hasWindows || isLocked) ? (isLocked ? 0 : isActive ? -6 : isAssociated ? -4 : isCurrent ? -2.5 : 0) : 0
         )
+        segment.containerLayer.zPosition = isLocked ? 42 : isActive ? 30 : isAssociated ? 18 : isCurrent ? 10 : 0
+        segment.containerLayer.transform = (isActive || isAssociated)
+            ? CATransform3DMakeScale(isActive ? 1.03 : 1.015, isActive ? 1.03 : 1.015, 1)
+            : CATransform3DIdentity
+        segment.containerLayer.shadowPath = (hasWindows || isLocked)
+            ? CGPath(
+                roundedRect: segment.containerLayer.bounds,
+                cornerWidth: segment.containerLayer.cornerRadius,
+                cornerHeight: segment.containerLayer.cornerRadius,
+                transform: nil
+            )
+            : nil
+
+        applySpaceLaneContentVisualState(
+            segment,
+            isLocked: isLocked,
+            usesLightActiveFill: resolvedTheme == .dark && hasWindows && !isLocked && (isActive || isAssociated)
+        )
+    }
+
+    private func applySpaceLaneContentVisualState(
+        _ segment: SpaceLaneSegmentLayers,
+        isLocked: Bool,
+        usesLightActiveFill: Bool
+    ) {
+        let primaryTextColor: NSColor = isLocked
+            ? .white
+            : usesLightActiveFill
+                ? NSColor.black.withAlphaComponent(0.82)
+                : themePalette.spaceLanePrimaryText
+        let secondaryTextColor: NSColor = isLocked
+            ? .white
+            : usesLightActiveFill
+                ? NSColor.black.withAlphaComponent(0.58)
+                : themePalette.spaceLaneSecondaryText
+        let markerTextColor: NSColor = isLocked
+            ? .white
+            : usesLightActiveFill
+                ? NSColor.black.withAlphaComponent(0.62)
+                : themePalette.spaceLaneSecondaryText.withAlphaComponent(segment.space.isCurrent ? 0.72 : 0.54)
+        let blockColor: NSColor = isLocked
+            ? .white
+            : usesLightActiveFill
+                ? NSColor.black.withAlphaComponent(0.20)
+                : spaceLaneOccupiedColor.withAlphaComponent(segment.space.isCurrent ? 0.72 : 0.58)
+
+        segment.labelLayer.foregroundColor = primaryTextColor.cgColor
+        segment.countLayer.foregroundColor = secondaryTextColor.cgColor
+        segment.appLayer.foregroundColor = (segment.space.type == .fullscreen
+            ? primaryTextColor
+            : secondaryTextColor
+        ).cgColor
+        for splitAppLayer in segment.splitAppLayers {
+            splitAppLayer.foregroundColor = primaryTextColor.cgColor
+        }
+
+        for block in segment.windowBlocks {
+            block.backgroundColor = blockColor.cgColor
+        }
+
+        (segment.fullscreenMarkerLayer as? CAShapeLayer)?.strokeColor = markerTextColor.cgColor
     }
 
     private func shouldScrollSpaceLane(for event: NSEvent) -> Bool {
@@ -1944,45 +4798,162 @@
             y: locationInView.y - glassLayer.frame.minY - laneLayer.frame.minY - spaceLaneContentLayer.frame.minY
         )
 
-        return spaceLaneSegments.first { segment in
-            segment.containerLayer.frame.contains(locationInSpaceLaneContent)
+        for group in spaceLaneDisplayGroups where group.containerLayer.frame.contains(locationInSpaceLaneContent) {
+            let locationInGroup = CGPoint(
+                x: locationInSpaceLaneContent.x - group.containerLayer.frame.minX,
+                y: locationInSpaceLaneContent.y - group.containerLayer.frame.minY
+            )
+            if let segment = group.segments.first(where: { $0.containerLayer.frame.contains(locationInGroup) }) {
+                return segment
+            }
         }
+
+        return nil
     }
 
     private func spaceLaneSegment(spaceID: UInt64) -> SpaceLaneSegmentLayers? {
         spaceLaneSegments.first { $0.space.id == spaceID }
     }
 
-    private func appShelfItem(at windowLocation: CGPoint) -> AppShelfItemLayers? {
+    private func viewModeToggleButtonContains(windowLocation: CGPoint) -> Bool {
         let locationInView = convert(windowLocation, from: nil)
-        let locationInShelfContent = CGPoint(
-            x: locationInView.x - glassLayer.frame.minX - shelfLayer.frame.minX - appShelfContentLayer.frame.minX,
-            y: locationInView.y - glassLayer.frame.minY - shelfLayer.frame.minY - appShelfContentLayer.frame.minY
+        let locationInGlass = CGPoint(
+            x: locationInView.x - glassLayer.frame.minX,
+            y: locationInView.y - glassLayer.frame.minY
         )
+        let hitOutset = (ViewModeToggleMetrics.hitSize - ViewModeToggleMetrics.visualSize) / 2
+        return viewModeToggleButtonLayer.frame
+            .insetBy(dx: -hitOutset, dy: -hitOutset)
+            .contains(locationInGlass)
+    }
+
+    private func themeToggleButtonContains(windowLocation: CGPoint) -> Bool {
+        let locationInView = convert(windowLocation, from: nil)
+        let locationInGlass = CGPoint(
+            x: locationInView.x - glassLayer.frame.minX,
+            y: locationInView.y - glassLayer.frame.minY
+        )
+        let hitOutset = (ViewModeToggleMetrics.hitSize - ViewModeToggleMetrics.visualSize) / 2
+        return themeToggleButtonLayer.frame
+            .insetBy(dx: -hitOutset, dy: -hitOutset)
+            .contains(locationInGlass)
+    }
+
+    private func clickViewModeToggleButton(source: String) {
+        DevelopmentDiagnostics.log("quickSwitch.view.clickWaterfallViewModeToggle", [
+            "source": source,
+            "currentMode": waterfallViewMode.rawValue,
+            "targetMode": nextWaterfallViewMode.rawValue
+        ])
+        lastMouseCommand = "click-view-toggle"
+        if !mouseCommandsApplied.contains("click-view-toggle") {
+            mouseCommandsApplied.append("click-view-toggle")
+        }
+        isViewModeToggleButtonHovered = false
+        suppressViewModeToggleHoverPreview = true
+        onToggleWaterfallViewMode?()
+    }
+
+    private func clickThemeToggleButton(source: String) {
+        DevelopmentDiagnostics.log("quickSwitch.view.clickThemeToggle", [
+            "source": source,
+            "currentTheme": resolvedTheme.rawValue,
+            "targetTheme": nextThemePreference.rawValue
+        ])
+        lastMouseCommand = "click-theme-toggle"
+        if !mouseCommandsApplied.contains("click-theme-toggle") {
+            mouseCommandsApplied.append("click-theme-toggle")
+        }
+        isThemeToggleButtonHovered = false
+        suppressThemeToggleHoverPreview = true
+        onToggleTheme?()
+    }
+
+    private func appShelfItem(at windowLocation: CGPoint) -> AppShelfItemLayers? {
+        let locationInShelfContent = appShelfContentLocation(at: windowLocation)
 
         return appShelfItems.first { item in
-            item.containerLayer.frame.contains(locationInShelfContent)
+            interactiveFrame(for: item.containerLayer).contains(locationInShelfContent)
         }
+    }
+
+    private func appShelfIconItem(at windowLocation: CGPoint) -> AppShelfItemLayers? {
+        let locationInAppShelfContent = appShelfContentLocation(at: windowLocation)
+
+        return appShelfItems.first { item in
+            let itemFrame = interactiveFrame(for: item.containerLayer)
+            let locationInItem = CGPoint(
+                x: locationInAppShelfContent.x - itemFrame.minX,
+                y: locationInAppShelfContent.y - itemFrame.minY
+            )
+            return interactiveFrame(for: item.iconLayer).contains(locationInItem)
+        }
+    }
+
+    private func appShelfContentLocation(at windowLocation: CGPoint) -> CGPoint {
+        let locationInView = convert(windowLocation, from: nil)
+        let glassFrame = interactiveFrame(for: glassLayer)
+        let shelfFrame = interactiveFrame(for: shelfLayer)
+        let appShelfContentFrame = interactiveFrame(for: appShelfContentLayer)
+
+        return CGPoint(
+            x: locationInView.x - glassFrame.minX - shelfFrame.minX - appShelfContentFrame.minX,
+            y: locationInView.y - glassFrame.minY - shelfFrame.minY - appShelfContentFrame.minY
+        )
+    }
+
+    private func appShelfItemCenterWindowLocation(for appGroupIndex: Int) -> CGPoint? {
+        guard let item = appShelfItems.first(where: { $0.item.appGroupIndex == appGroupIndex }) else {
+            return nil
+        }
+
+        let pointInView = CGPoint(
+            x: glassLayer.frame.minX
+                + shelfLayer.frame.minX
+                + appShelfContentLayer.frame.minX
+                + item.containerLayer.frame.midX,
+            y: glassLayer.frame.minY
+                + shelfLayer.frame.minY
+                + appShelfContentLayer.frame.minY
+                + item.containerLayer.frame.midY
+        )
+        return convert(pointInView, to: nil)
     }
 
     private func waterfallCard(at windowLocation: CGPoint) -> WaterfallCardLayers? {
         let locationInView = convert(windowLocation, from: nil)
+        let glassFrame = interactiveFrame(for: glassLayer)
+        let waterfallFrame = interactiveFrame(for: waterfallLayer)
+        let waterfallContentFrame = interactiveFrame(for: waterfallContentLayer)
         let locationInWaterfallContent = CGPoint(
-            x: locationInView.x - glassLayer.frame.minX - waterfallLayer.frame.minX - waterfallContentLayer.frame.minX,
-            y: locationInView.y - glassLayer.frame.minY - waterfallLayer.frame.minY - waterfallContentLayer.frame.minY
+            x: locationInView.x - glassFrame.minX - waterfallFrame.minX - waterfallContentFrame.minX,
+            y: locationInView.y - glassFrame.minY - waterfallFrame.minY - waterfallContentFrame.minY
         )
 
-        for column in waterfallColumns where column.containerLayer.frame.contains(locationInWaterfallContent) {
+        for column in waterfallColumns where interactiveFrame(for: column.containerLayer).contains(locationInWaterfallContent) {
+            let columnFrame = interactiveFrame(for: column.containerLayer)
+            let cardsClipFrame = interactiveFrame(for: column.cardsClipLayer)
             let locationInColumn = CGPoint(
-                x: locationInWaterfallContent.x - column.containerLayer.frame.minX,
-                y: locationInWaterfallContent.y - column.containerLayer.frame.minY
+                x: locationInWaterfallContent.x - columnFrame.minX,
+                y: locationInWaterfallContent.y - columnFrame.minY
             )
-            if let card = column.cards.first(where: { $0.containerLayer.frame.contains(locationInColumn) }) {
+            guard cardsClipFrame.contains(locationInColumn) else {
+                continue
+            }
+            let locationInCardsClip = CGPoint(
+                x: locationInColumn.x - cardsClipFrame.minX,
+                y: locationInColumn.y - cardsClipFrame.minY
+            )
+            if let card = column.cards.first(where: { interactiveFrame(for: $0.containerLayer).contains(locationInCardsClip) }) {
                 return card
             }
         }
 
         return nil
+    }
+
+    private func interactiveFrame(for layer: CALayer) -> CGRect {
+        layer.presentation()?.frame ?? layer.frame
     }
 
     private func waterfallCard(appGroupIndex: Int, windowIndex: Int) -> WaterfallCardLayers? {
@@ -1992,23 +4963,70 @@
             .first(where: { $0.item.windowIndex == windowIndex })
     }
 
+    private func waterfallCard(appGroupIndex: Int, windowIndexSymbol: String) -> WaterfallCardLayers? {
+        guard let ordinal = Self.appShelfIndexSymbols.firstIndex(of: windowIndexSymbol),
+              ordinal < Self.appShelfIndexSymbols.count
+        else {
+            return nil
+        }
+        return waterfallCard(appGroupIndex: appGroupIndex, windowIndex: ordinal)
+    }
+
+    private func waterfallCard(windowID: UInt32) -> WaterfallCardLayers? {
+        waterfallColumns
+            .lazy
+            .flatMap(\.cards)
+            .first(where: { $0.item.window.id == windowID })
+    }
+
     private func layoutSpaceLaneSegmentContents(_ segment: SpaceLaneSegmentLayers) {
         let bounds = segment.containerLayer.bounds
+        let splitAppNames = splitViewAppNames(for: segment.space)
+        let isSplitView = splitAppNames.count >= 2
         segment.labelLayer.frame = CGRect(x: 10, y: bounds.height - 29, width: max(1, bounds.width - 48), height: 20)
         segment.countLayer.frame = CGRect(x: bounds.width - 34, y: bounds.height - 29, width: 24, height: 20)
+        segment.countLayer.string = isSplitView ? "" : "\(segment.space.windowCount)"
+        segment.countLayer.isHidden = isSplitView
         if segment.space.type == .fullscreen {
             let markerFrame = fullscreenMarkerFrame(in: bounds)
-            segment.appLayer.frame = CGRect(
-                x: 8,
-                y: markerFrame.midY - 8.5,
-                width: max(1, bounds.width - 16),
-                height: 17
-            )
+            segment.appLayer.isHidden = isSplitView
+            if isSplitView {
+                let labelY = markerFrame.midY - 8.5
+                let halfWidth = markerFrame.width / 2
+                for (index, splitAppLayer) in segment.splitAppLayers.enumerated() {
+                    let x = markerFrame.minX + CGFloat(index) * halfWidth
+                    splitAppLayer.isHidden = false
+                    splitAppLayer.frame = CGRect(
+                        x: x + 4,
+                        y: labelY,
+                        width: max(1, halfWidth - 8),
+                        height: 17
+                    )
+                }
+            } else {
+                segment.appLayer.frame = CGRect(
+                    x: 8,
+                    y: markerFrame.midY - 8.5,
+                    width: max(1, bounds.width - 16),
+                    height: 17
+                )
+                for splitAppLayer in segment.splitAppLayers {
+                    splitAppLayer.isHidden = true
+                }
+            }
         } else {
+            segment.appLayer.isHidden = false
             segment.appLayer.frame = CGRect(x: 10, y: 9, width: max(1, bounds.width - 20), height: 17)
+            for splitAppLayer in segment.splitAppLayers {
+                splitAppLayer.isHidden = true
+            }
         }
         if let fullscreenMarkerLayer = segment.fullscreenMarkerLayer {
-            layoutFullscreenMarkerLayer(fullscreenMarkerLayer, in: bounds)
+            layoutFullscreenMarkerLayer(
+                fullscreenMarkerLayer,
+                in: bounds,
+                isSplitView: isSplitView
+            )
         }
 
         let blockGap: CGFloat = 5
@@ -2069,53 +5087,72 @@
     private func layoutAppShelfItemContents(_ item: AppShelfItemLayers, iconSize: CGFloat) {
         let bounds = item.containerLayer.bounds
         let isSelected = item.item.appGroupIndex == effectiveSelection?.appGroupIndex
-        let showsSelectedVisual = shouldShowSelectedVisual(isSelected)
         let isHovered = item.item.appGroupIndex == effectiveHoveredAppGroupIndex
+        let showsSelectedVisual = shouldShowSelectedVisual(isSelected: isSelected, isHovered: isHovered)
         let isSpaceFocused = spaceFocusWindowCount(for: item.item.appGroupIndex) > 0
+        let magneticState = appShelfMagneticState(for: item)
         let visualIconSize = appShelfVisualIconSize(
             forBaseIconSize: iconSize,
             selected: showsSelectedVisual,
             hovered: isHovered,
-            spaceFocused: isSpaceFocused
+            spaceFocused: isSpaceFocused,
+            magneticState: magneticState
         )
-        let backgroundPadding: CGFloat = (showsSelectedVisual || isHovered)
-            ? 4
-            : isSpaceFocused
-                ? 6
-                : 2
+        let backgroundPadding: CGFloat = isSpaceFocused ? 6 : 2
         let iconX = (bounds.width - visualIconSize) / 2
-        let iconY = bounds.height - visualIconSize - 2
+        let iconY = bounds.height - visualIconSize - 2 + magneticState.lift
         let badgeText = appShelfBadgeText(for: item)
         let badgeWidth = max(18, CGFloat(badgeText.count) * 7 + 8)
+
+        let previousBackgroundFrame = item.backgroundLayer.presentation()?.frame ?? item.backgroundLayer.frame
+        let previousIconFrame = item.iconLayer.presentation()?.frame ?? item.iconLayer.frame
+        let previousIndexFrame = item.indexLayer.presentation()?.frame ?? item.indexLayer.frame
+        let previousBadgeFrame = item.badgeLayer.presentation()?.frame ?? item.badgeLayer.frame
+        let previousCloseFrame = item.closeButton.containerLayer.presentation()?.frame
+            ?? item.closeButton.containerLayer.frame
 
         item.containerLayer.zPosition = appShelfZPosition(
             selected: showsSelectedVisual,
             hovered: isHovered,
-            spaceFocused: isSpaceFocused
+            spaceFocused: isSpaceFocused,
+            magneticState: magneticState
         )
         item.backgroundLayer.backgroundColor = appShelfBackgroundColor(
             selected: showsSelectedVisual,
             hovered: isHovered,
-            spaceFocused: isSpaceFocused
+            spaceFocused: isSpaceFocused,
+            magneticState: magneticState
         ).cgColor
-        item.backgroundLayer.borderColor = (showsSelectedVisual
-            ? NSColor.controlAccentColor.withAlphaComponent(0.40)
-            : isHovered
-                ? NSColor.controlAccentColor.withAlphaComponent(0.36)
-                : NSColor.clear
-        ).cgColor
-        item.backgroundLayer.borderWidth = (showsSelectedVisual || isHovered) ? 1 : 0
+        item.backgroundLayer.borderColor = NSColor.clear.cgColor
+        item.backgroundLayer.borderWidth = 0
+        item.containerLayer.borderColor = NSColor.clear.cgColor
+        item.containerLayer.borderWidth = 0
+        item.iconLayer.borderColor = NSColor.clear.cgColor
+        item.iconLayer.borderWidth = 0
         item.backgroundLayer.shadowColor = NSColor.black.cgColor
-        item.backgroundLayer.shadowOpacity = showsSelectedVisual ? 0.11 : isHovered ? 0.07 : isSpaceFocused ? 0.18 : 0
-        item.backgroundLayer.shadowRadius = showsSelectedVisual ? 10 : isHovered ? 8 : isSpaceFocused ? 18 : 0
-        item.backgroundLayer.shadowOffset = CGSize(width: 0, height: isSpaceFocused ? -4 : -2)
+        item.backgroundLayer.shadowOpacity = appShelfShadowOpacity(
+            selected: showsSelectedVisual,
+            hovered: isHovered,
+            spaceFocused: isSpaceFocused,
+            magneticState: magneticState
+        )
+        item.backgroundLayer.shadowRadius = appShelfShadowRadius(
+            selected: showsSelectedVisual,
+            hovered: isHovered,
+            spaceFocused: isSpaceFocused,
+            magneticState: magneticState
+        )
+        item.backgroundLayer.shadowOffset = CGSize(
+            width: 0,
+            height: isSpaceFocused ? -4 : magneticState.isNeighbor ? -1 : -2
+        )
         item.backgroundLayer.frame = CGRect(
             x: iconX - backgroundPadding,
             y: iconY - backgroundPadding,
             width: visualIconSize + backgroundPadding * 2,
             height: visualIconSize + backgroundPadding * 2
         )
-        item.backgroundLayer.shadowPath = (showsSelectedVisual || isHovered || isSpaceFocused)
+        item.backgroundLayer.shadowPath = isSpaceFocused
             ? CGPath(
                 roundedRect: item.backgroundLayer.bounds,
                 cornerWidth: item.backgroundLayer.cornerRadius,
@@ -2124,7 +5161,15 @@
             )
             : nil
         item.iconLayer.frame = CGRect(x: iconX, y: iconY, width: visualIconSize, height: visualIconSize)
+        layoutAppShelfIndexLayer(
+            item.indexLayer,
+            iconFrame: item.iconLayer.frame,
+            iconSize: visualIconSize,
+            itemBounds: bounds,
+            highlighted: showsSelectedVisual || isHovered
+        )
         item.labelLayer.contentsScale = backingScaleFactor
+        item.labelLayer.foregroundColor = themePalette.appShelfLabelText.cgColor
         item.labelLayer.frame = CGRect(x: 0, y: 0, width: bounds.width, height: 14)
         item.badgeLayer.string = badgeText
         item.badgeLayer.isHidden = badgeText.isEmpty
@@ -2149,6 +5194,72 @@
         )
         item.selectedIndicatorLayer.frame = .zero
         item.selectedIndicatorLayer.backgroundColor = NSColor.clear.cgColor
+
+        animateAppShelfLayerFrame(item.backgroundLayer, from: previousBackgroundFrame)
+        animateAppShelfLayerFrame(item.iconLayer, from: previousIconFrame)
+        animateAppShelfLayerFrame(item.indexLayer, from: previousIndexFrame)
+        animateAppShelfLayerFrame(item.badgeLayer, from: previousBadgeFrame)
+        animateAppShelfLayerFrame(item.closeButton.containerLayer, from: previousCloseFrame)
+    }
+
+    private var appShelfIndexColor: NSColor {
+        themePalette.appShelfIndexText
+    }
+
+    private var appShelfIndexHighlightedColor: NSColor {
+        themePalette.appShelfIndexHighlightedText
+    }
+
+    private func appShelfIndexFont(size: CGFloat) -> NSFont {
+        for fontName in ["Bradley Hand ITC", "Noteworthy-Light", "Marker Felt", "Snell Roundhand"] {
+            if let font = NSFont(name: fontName, size: size) {
+                return font
+            }
+        }
+
+        return NSFont.monospacedSystemFont(ofSize: size, weight: .regular)
+    }
+
+    private func appShelfIndexText(forOrdinal ordinal: Int) -> String {
+        guard ordinal >= 0 else { return "" }
+        if ordinal < Self.appShelfIndexSymbols.count {
+            return Self.appShelfIndexSymbols[ordinal]
+        }
+
+        let overflowIndex = ordinal - Self.appShelfIndexSymbols.count
+        let prefix = Self.appShelfIndexSymbols[10 + (overflowIndex / 26) % 26]
+        let suffix = Self.appShelfIndexSymbols[10 + overflowIndex % 26]
+        return "\(prefix)\(suffix)"
+    }
+
+    private func layoutAppShelfIndexLayer(
+        _ layer: CATextLayer,
+        iconFrame: CGRect,
+        iconSize: CGFloat,
+        itemBounds: CGRect,
+        highlighted: Bool
+    ) {
+        let fontSize = iconSize <= AppShelfMetrics.minIconSize + 1
+            ? AppShelfMetrics.compressedIndexFontSize
+            : AppShelfMetrics.indexFontSize
+        layer.contentsScale = backingScaleFactor
+        layer.font = appShelfIndexFont(size: fontSize)
+        layer.fontSize = fontSize
+        layer.foregroundColor = (highlighted ? appShelfIndexHighlightedColor : appShelfIndexColor).cgColor
+        layer.opacity = 1
+
+        let indexWidth = AppShelfMetrics.indexWidth
+        let indexHeight = AppShelfMetrics.indexHeight
+        let preferredX = iconFrame.minX - indexWidth - 2
+        let clampedX = max(-7, min(itemBounds.width - indexWidth, preferredX))
+        let preferredY = iconFrame.maxY - indexHeight + 6
+        let clampedY = max(0, min(itemBounds.height - indexHeight, preferredY))
+        layer.frame = CGRect(
+            x: clampedX,
+            y: clampedY,
+            width: indexWidth,
+            height: indexHeight
+        )
     }
 
     private func appShelfRows() -> [[AppShelfItemLayers]] {
@@ -2173,16 +5284,130 @@
         debugHoveredAppGroupIndex ?? hoveredAppGroupIndex
     }
 
+    private var appShelfMagneticHoverEnabled: Bool {
+        !NSWorkspace.shared.accessibilityDisplayShouldReduceMotion
+    }
+
+    private func appShelfMagneticState(for item: AppShelfItemLayers) -> AppShelfMagneticState {
+        guard appShelfMagneticHoverEnabled,
+              let hoveredAppGroupIndex = effectiveHoveredAppGroupIndex,
+              item.item.appGroupIndex == hoveredAppGroupIndex
+        else {
+            return AppShelfMagneticState(influence: 0, lift: 0)
+        }
+
+        return AppShelfMagneticState(
+            influence: 1,
+            lift: AppShelfMetrics.magneticHoverLift
+        )
+    }
+
+    private func animateAppShelfLayerFrame(_ layer: CALayer, from previousFrame: CGRect) {
+        guard appShelfMagneticHoverEnabled,
+              previousFrame.width > 0,
+              previousFrame.height > 0,
+              appShelfFrameIsFinite(previousFrame),
+              appShelfFrameIsFinite(layer.frame)
+        else {
+            layer.removeAnimation(forKey: "appShelfMagneticPosition")
+            layer.removeAnimation(forKey: "appShelfMagneticBounds")
+            return
+        }
+
+        let previousPosition = CGPoint(x: previousFrame.midX, y: previousFrame.midY)
+        let previousBounds = CGRect(origin: .zero, size: previousFrame.size)
+        let nextPosition = layer.position
+        let nextBounds = layer.bounds
+        let moved = abs(previousPosition.x - nextPosition.x) > 0.25
+            || abs(previousPosition.y - nextPosition.y) > 0.25
+        let resized = abs(previousBounds.width - nextBounds.width) > 0.25
+            || abs(previousBounds.height - nextBounds.height) > 0.25
+
+        guard moved || resized else { return }
+
+        let timing = CAMediaTimingFunction(name: AppShelfMetrics.magneticAnimationTimingName)
+        if moved {
+            let animation = CABasicAnimation(keyPath: "position")
+            animation.fromValue = previousPosition
+            animation.toValue = nextPosition
+            animation.duration = AppShelfMetrics.magneticAnimationDuration
+            animation.timingFunction = timing
+            animation.isRemovedOnCompletion = true
+            layer.add(animation, forKey: "appShelfMagneticPosition")
+        }
+        if resized {
+            let animation = CABasicAnimation(keyPath: "bounds")
+            animation.fromValue = previousBounds
+            animation.toValue = nextBounds
+            animation.duration = AppShelfMetrics.magneticAnimationDuration
+            animation.timingFunction = timing
+            animation.isRemovedOnCompletion = true
+            layer.add(animation, forKey: "appShelfMagneticBounds")
+        }
+    }
+
+    private func appShelfFrameIsFinite(_ frame: CGRect) -> Bool {
+        frame.origin.x.isFinite
+            && frame.origin.y.isFinite
+            && frame.size.width.isFinite
+            && frame.size.height.isFinite
+    }
+
     private var activeSpaceFocusID: UInt64? {
-        hoveredSpaceLaneID
+        guard case .space(let spaceID) = hoverTarget else { return nil }
+
+        if hoverTargetSource == .debug {
+            return spaceID
+        }
+
+        guard let window else { return nil }
+        let currentMouseLocation = window.mouseLocationOutsideOfEventStream
+        guard let segment = spaceLaneSegment(at: currentMouseLocation),
+              segment.space.id == spaceID
+        else {
+            return nil
+        }
+        return spaceID
+    }
+
+    private var appHoverAssociatedSpaceIDs: Set<UInt64> {
+        guard case .app(let appGroupIndex) = hoverTarget else { return [] }
+        return Set(
+            waterfallColumns
+                .first { $0.column.appGroupIndex == appGroupIndex }?
+                .cards
+                .compactMap(\.item.primarySpaceID) ?? []
+        )
+    }
+
+    private var appIconHoverLinkedAppGroupIndex: Int? {
+        if let debugHoveredAppGroupIndex {
+            return debugHoveredAppGroupIndex
+        }
+        guard case .app(let appGroupIndex) = hoverTarget else { return nil }
+        return appGroupIndex
+    }
+
+    private var appHoverAssociatedSpaceLabels: [String] {
+        guard !appHoverAssociatedSpaceIDs.isEmpty else { return [] }
+        return currentViewModel?.displays
+            .flatMap(\.spaces)
+            .filter { appHoverAssociatedSpaceIDs.contains($0.id) }
+            .map(\.label)
+            .sorted() ?? []
+    }
+
+    private var windowHoverAssociatedSpaceID: UInt64? {
+        guard case .window(_, _, let spaceID) = hoverTarget else { return nil }
+        return spaceID
     }
 
     private var isSpaceAssociationActive: Bool {
         activeSpaceFocusID != nil
     }
 
-    private func shouldShowSelectedVisual(_ isSelected: Bool) -> Bool {
-        isSelected && !isSpaceAssociationActive
+    private func shouldShowSelectedVisual(isSelected: Bool, isHovered: Bool) -> Bool {
+        isSelected && isHovered && !isSpaceAssociationActive
     }
 
     private func spaceFocusedAppGroupIndexes() -> [Int] {
@@ -2229,6 +5454,10 @@
             return "none"
         }
 
+        guard !isHorizontalMasonryMode else {
+            return "visible"
+        }
+
         let visibleMinX = waterfallScrollOffset
         let visibleMaxX = waterfallScrollOffset + waterfallLayer.bounds.width
         if column.containerLayer.frame.maxX < visibleMinX + WaterfallMetrics.gap {
@@ -2244,7 +5473,8 @@
         forBaseIconSize iconSize: CGFloat,
         selected: Bool,
         hovered: Bool,
-        spaceFocused: Bool
+        spaceFocused: Bool,
+        magneticState: AppShelfMagneticState
     ) -> CGFloat {
         if selected || hovered {
             return AppShelfMetrics.selectedIconSize
@@ -2252,10 +5482,19 @@
         if spaceFocused {
             return min(AppShelfMetrics.selectedIconSize, iconSize + 8)
         }
-        return iconSize
+        guard magneticState.isNeighbor else {
+            return iconSize
+        }
+        let growth = AppShelfMetrics.hoverIconSize - iconSize
+        return iconSize + growth * magneticState.influence
     }
 
-    private func appShelfZPosition(selected: Bool, hovered: Bool, spaceFocused: Bool) -> CGFloat {
+    private func appShelfZPosition(
+        selected: Bool,
+        hovered: Bool,
+        spaceFocused: Bool,
+        magneticState: AppShelfMagneticState
+    ) -> CGFloat {
         switch (selected, hovered, spaceFocused) {
         case (true, true, _):
             return 30
@@ -2266,21 +5505,44 @@
         case (false, false, true):
             return 12
         case (false, false, false):
-            return 0
+            return magneticState.isNeighbor ? 6 + magneticState.influence : 0
         }
     }
 
-    private func appShelfBackgroundColor(selected: Bool, hovered: Bool, spaceFocused: Bool) -> NSColor {
-        if selected {
-            return NSColor.controlAccentColor.withAlphaComponent(0.14)
-        }
-        if hovered {
-            return NSColor.controlAccentColor.withAlphaComponent(0.13)
-        }
+    private func appShelfBackgroundColor(
+        selected: Bool,
+        hovered: Bool,
+        spaceFocused: Bool,
+        magneticState: AppShelfMagneticState
+    ) -> NSColor {
         if spaceFocused {
-            return NSColor.controlAccentColor.withAlphaComponent(0.14)
+            return themePalette.appShelfBackgroundSpaceFocused
         }
         return .clear
+    }
+
+    private func appShelfShadowOpacity(
+        selected: Bool,
+        hovered: Bool,
+        spaceFocused: Bool,
+        magneticState: AppShelfMagneticState
+    ) -> Float {
+        if spaceFocused {
+            return 0.18
+        }
+        return 0
+    }
+
+    private func appShelfShadowRadius(
+        selected: Bool,
+        hovered: Bool,
+        spaceFocused: Bool,
+        magneticState: AppShelfMagneticState
+    ) -> CGFloat {
+        if spaceFocused {
+            return 18
+        }
+        return 0
     }
 
     private func appShelfBadgeText(for item: AppShelfItemLayers) -> String {
@@ -2302,6 +5564,10 @@
         return item.item.windowCount > 1 ? "\(item.item.windowCount)" : ""
     }
 
+    private var waterfallAppHoverHeaderFillColor: NSColor {
+        themePalette.columnHeaderHoverBackground
+    }
+
     private var appShelfMaxScrollOffset: CGFloat {
         max(0, appShelfContentWidth - shelfLayer.bounds.width)
     }
@@ -2311,17 +5577,24 @@
     }
 
     private func layoutWaterfallColumns() {
+        if isHorizontalMasonryMode {
+            layoutHorizontalMasonryWaterfall()
+            return
+        }
+
         guard !waterfallColumns.isEmpty else {
             waterfallContentWidth = waterfallLayer.bounds.width
             waterfallScrollOffset = 0
+            horizontalMasonryContentHeight = waterfallLayer.bounds.height
+            horizontalMasonryScrollOffset = 0
             waterfallContentLayer.frame = waterfallLayer.bounds
             return
         }
 
         let columnWidth = waterfallColumnWidth()
-        let totalWidth = WaterfallMetrics.columnPadding * 2
-            + CGFloat(waterfallColumns.count) * columnWidth
+        let columnsWidth = CGFloat(waterfallColumns.count) * columnWidth
             + CGFloat(max(0, waterfallColumns.count - 1)) * WaterfallMetrics.gap
+        let totalWidth = WaterfallMetrics.contentHorizontalPadding * 2 + columnsWidth
         waterfallContentWidth = max(waterfallLayer.bounds.width, totalWidth)
         waterfallScrollOffset = clampedWaterfallAlignmentOffset(waterfallScrollOffset)
         waterfallContentLayer.frame = CGRect(
@@ -2331,7 +5604,7 @@
             height: waterfallLayer.bounds.height
         )
 
-        var x = WaterfallMetrics.columnPadding
+        var x = waterfallColumnStartX(columnsWidth: columnsWidth)
         for column in waterfallColumns {
             column.containerLayer.frame = CGRect(
                 x: x,
@@ -2344,12 +5617,191 @@
         }
     }
 
+    private func layoutHorizontalMasonryWaterfall() {
+        guard !waterfallColumns.isEmpty else {
+            waterfallContentWidth = waterfallLayer.bounds.width
+            waterfallScrollOffset = 0
+            horizontalMasonryContentHeight = waterfallLayer.bounds.height
+            horizontalMasonryScrollOffset = 0
+            waterfallContentLayer.frame = waterfallLayer.bounds
+            return
+        }
+
+        let layout = horizontalMasonryLayout()
+        waterfallContentWidth = waterfallLayer.bounds.width
+        waterfallScrollOffset = 0
+        horizontalMasonryContentHeight = layout.contentHeight
+        horizontalMasonryScrollOffset = clampedHorizontalMasonryOffset(horizontalMasonryScrollOffset)
+        waterfallContentLayer.frame = horizontalMasonryContentFrame()
+
+        for column in waterfallColumns {
+            column.containerLayer.frame = CGRect(
+                x: 0,
+                y: 0,
+                width: waterfallContentWidth,
+                height: horizontalMasonryContentHeight
+            )
+            column.containerLayer.masksToBounds = false
+            column.containerLayer.backgroundColor = NSColor.clear.cgColor
+            column.containerLayer.borderColor = NSColor.clear.cgColor
+            column.containerLayer.borderWidth = 0
+            column.containerLayer.shadowOpacity = 0
+            column.containerLayer.shadowRadius = 0
+            column.containerLayer.shadowOffset = .zero
+            column.cardsClipLayer.frame = column.containerLayer.bounds
+            column.cardsClipLayer.masksToBounds = false
+            column.headerLayer.isHidden = true
+            column.appNameLayer.isHidden = true
+            column.countLayer.isHidden = true
+
+            for card in column.cards {
+                card.containerLayer.transform = CATransform3DIdentity
+                if let frame = layout.cardFramesByWindowID[card.item.window.id] {
+                    card.containerLayer.frame = frame
+                } else {
+                    card.containerLayer.frame = .zero
+                }
+                layoutWaterfallCard(card)
+            }
+        }
+    }
+
+    private struct HorizontalMasonryLayout {
+        let contentHeight: CGFloat
+        let cardFramesByWindowID: [UInt32: CGRect]
+    }
+
+    private func horizontalMasonryLayout() -> HorizontalMasonryLayout {
+        let cards = horizontalMasonryCardsInPlacementOrder()
+        guard !cards.isEmpty else {
+            return HorizontalMasonryLayout(
+                contentHeight: waterfallLayer.bounds.height,
+                cardFramesByWindowID: [:]
+            )
+        }
+
+        let viewportWidth = max(1, waterfallLayer.bounds.width)
+        let availableWidth = max(
+            HorizontalMasonryMetrics.cardMinWidth,
+            viewportWidth - HorizontalMasonryMetrics.horizontalPadding * 2
+        )
+        let maximumLaneCount = max(
+            1,
+            Int(
+                floor(
+                    (availableWidth + HorizontalMasonryMetrics.horizontalGap)
+                        / (HorizontalMasonryMetrics.cardMinWidth + HorizontalMasonryMetrics.horizontalGap)
+                )
+            )
+        )
+        let laneCount = min(maximumLaneCount, max(1, cards.count))
+        let fittingWidth = (
+            availableWidth - CGFloat(max(0, laneCount - 1)) * HorizontalMasonryMetrics.horizontalGap
+        ) / CGFloat(laneCount)
+        let cardWidth = floor(
+            min(
+                HorizontalMasonryMetrics.cardMaxWidth,
+                max(HorizontalMasonryMetrics.cardMinWidth, fittingWidth)
+            )
+        )
+        let usedWidth = CGFloat(laneCount) * cardWidth
+            + CGFloat(max(0, laneCount - 1)) * HorizontalMasonryMetrics.horizontalGap
+        let startX = max(
+            HorizontalMasonryMetrics.horizontalPadding,
+            (viewportWidth - usedWidth) / 2
+        )
+
+        var laneHeights = Array(repeating: CGFloat(0), count: laneCount)
+        var plannedFrames: [(windowID: UInt32, x: CGFloat, top: CGFloat, width: CGFloat, height: CGFloat)] = []
+
+        for card in cards {
+            let laneIndex = laneHeights.enumerated().min { lhs, rhs in
+                if abs(lhs.element - rhs.element) > 0.5 {
+                    return lhs.element < rhs.element
+                }
+                return lhs.offset < rhs.offset
+            }?.offset ?? 0
+            let cardHeight = HorizontalMasonryMetrics.cardHeight
+            let x = startX + CGFloat(laneIndex) * (cardWidth + HorizontalMasonryMetrics.horizontalGap)
+            let top = HorizontalMasonryMetrics.verticalPadding + laneHeights[laneIndex]
+            plannedFrames.append((
+                windowID: card.item.window.id,
+                x: x,
+                top: top,
+                width: cardWidth,
+                height: cardHeight
+            ))
+            laneHeights[laneIndex] += cardHeight + HorizontalMasonryMetrics.verticalGap
+        }
+
+        let tallestLane = laneHeights.max().map {
+            max(0, $0 - HorizontalMasonryMetrics.verticalGap)
+        } ?? 0
+        let contentHeight = max(
+            waterfallLayer.bounds.height,
+            HorizontalMasonryMetrics.verticalPadding * 2 + tallestLane
+        )
+        let frames = Dictionary(
+            uniqueKeysWithValues: plannedFrames.map { planned in
+                (
+                    planned.windowID,
+                    CGRect(
+                        x: planned.x,
+                        y: contentHeight - planned.top - planned.height,
+                        width: planned.width,
+                        height: planned.height
+                    )
+                )
+            }
+        )
+
+        return HorizontalMasonryLayout(contentHeight: contentHeight, cardFramesByWindowID: frames)
+    }
+
+    private func horizontalMasonryContentFrame() -> CGRect {
+        let contentHeight = max(waterfallLayer.bounds.height, horizontalMasonryContentHeight)
+        return CGRect(
+            x: 0,
+            y: waterfallLayer.bounds.height - contentHeight + horizontalMasonryScrollOffset,
+            width: waterfallLayer.bounds.width,
+            height: contentHeight
+        )
+    }
+
+    private func waterfallColumnStartX(columnsWidth: CGFloat) -> CGFloat {
+        guard currentViewModel?.lockedSpaceID != nil else {
+            return WaterfallMetrics.contentHorizontalPadding
+        }
+
+        let centeredStart = (waterfallContentWidth - columnsWidth) / 2
+        return max(WaterfallMetrics.contentHorizontalPadding, centeredStart)
+    }
+
     private func layoutWaterfallColumn(_ column: WaterfallColumnLayers) {
+        column.containerLayer.cornerRadius = 14
+        column.containerLayer.masksToBounds = true
+        column.containerLayer.backgroundColor = themePalette.columnBackground.cgColor
+        column.containerLayer.shadowOpacity = 0
+        column.containerLayer.shadowRadius = 0
+        column.containerLayer.shadowOffset = .zero
+        column.headerLayer.isHidden = false
+        column.appNameLayer.isHidden = false
+        column.countLayer.isHidden = false
+
         let bounds = column.containerLayer.bounds
+        let cardsClipFrame = CGRect(
+            x: 0,
+            y: 0,
+            width: bounds.width,
+            height: max(1, bounds.height - WaterfallMetrics.headerHeight)
+        )
+        column.cardsClipLayer.frame = cardsClipFrame
+        column.cardsClipLayer.masksToBounds = true
         let isSpaceFocused = spaceFocusWindowCount(for: column.column.appGroupIndex) > 0
+        let isHovered = column.column.appGroupIndex == effectiveHoveredAppGroupIndex
         column.containerLayer.borderColor = (isSpaceFocused
-            ? NSColor.separatorColor.withAlphaComponent(0.38)
-            : NSColor.separatorColor.withAlphaComponent(0.24)
+            ? themePalette.columnBorder.withAlphaComponent(resolvedTheme == .dark ? 0.34 : 0.38)
+            : themePalette.columnBorder
         ).cgColor
         column.containerLayer.borderWidth = 1
         column.headerLayer.frame = CGRect(
@@ -2358,22 +5810,26 @@
             width: bounds.width,
             height: WaterfallMetrics.headerHeight
         )
-        column.headerLayer.backgroundColor = (isSpaceFocused
-            ? NSColor.systemFill.withAlphaComponent(0.10)
-            : NSColor.controlBackgroundColor.withAlphaComponent(0.52)
+        column.headerLayer.backgroundColor = (isHovered
+            ? waterfallAppHoverHeaderFillColor
+            : (isSpaceFocused
+                ? themePalette.columnHeaderSpaceFocusedBackground
+                : themePalette.columnHeaderBackground)
         ).cgColor
         column.appNameLayer.frame = CGRect(
-            x: WaterfallMetrics.columnPadding,
+            x: WaterfallMetrics.columnHeaderTextInset,
             y: bounds.height - 24,
-            width: max(1, bounds.width - 64),
+            width: max(1, bounds.width - WaterfallMetrics.columnHeaderTextInset * 2),
             height: 16
         )
+        column.appNameLayer.foregroundColor = themePalette.columnText.cgColor
         column.countLayer.frame = CGRect(
             x: bounds.width - 48,
             y: bounds.height - 24,
             width: 36,
             height: 16
         )
+        column.countLayer.foregroundColor = themePalette.columnSecondaryText.cgColor
 
         let appGroupIndex = column.column.appGroupIndex
         let verticalOffset = clampedWaterfallColumnOffset(
@@ -2382,10 +5838,10 @@
         )
         waterfallColumnScrollOffsets[appGroupIndex] = verticalOffset
 
-        let cardWidth = max(1, bounds.width - WaterfallMetrics.columnPadding * 2)
-        let firstCardTop = bounds.height
-            - WaterfallMetrics.headerHeight
-            - WaterfallMetrics.columnPadding
+        let cardWidth = max(1, bounds.width - WaterfallMetrics.columnHorizontalPadding * 2)
+        let firstCardTop = cardsClipFrame.height
+            - WaterfallMetrics.selectedCardScaleOverflow
+            - WaterfallMetrics.columnVerticalPadding
             + verticalOffset
 
         for card in column.cards {
@@ -2393,8 +5849,9 @@
             let y = firstCardTop
                 - WaterfallMetrics.cardHeight
                 - CGFloat(cardIndex) * (WaterfallMetrics.cardHeight + WaterfallMetrics.cardGap)
+            card.containerLayer.transform = CATransform3DIdentity
             card.containerLayer.frame = CGRect(
-                x: WaterfallMetrics.columnPadding,
+                x: WaterfallMetrics.columnHorizontalPadding,
                 y: y,
                 width: cardWidth,
                 height: WaterfallMetrics.cardHeight
@@ -2407,9 +5864,21 @@
         let bounds = card.containerLayer.bounds
         let isSelected = card.item.window.id == effectiveSelection?.windowID
         let isHovered = card.item.window.id == hoveredWindowID
-        applyWaterfallCardVisualState(card, selected: shouldShowSelectedVisual(isSelected), hovered: isHovered)
+        let isKeyboardFocused = card.item.window.id == keyboardFocusedWindowID
+        let isHorizontalAppDefaultFocused = isHorizontalAppDefaultCard(card)
+        let isAppLinked = isWaterfallCardAppLinked(card)
+        let shortcutFilterState = windowShortcutFilterState(for: card)
+        applyWaterfallCardVisualState(
+            card,
+            selected: shouldShowSelectedVisual(isSelected: isSelected, isHovered: isHovered)
+                || isKeyboardFocused
+                || isHorizontalAppDefaultFocused,
+            hovered: isHovered,
+            appLinked: isAppLinked,
+            shortcutFilterState: shortcutFilterState
+        )
 
-        let outerInset: CGFloat = 8
+        let outerInset: CGFloat = 0
         let titleBarHeight: CGFloat = 26
         let titleGap: CGFloat = 6
         let titleBarFrame = CGRect(
@@ -2439,18 +5908,21 @@
             width: max(1, titleBarFrame.width - 68),
             height: 16
         )
+        card.titleLayer.foregroundColor = themePalette.cardText.cgColor
         card.metaLayer.frame = CGRect(
             x: titleBarFrame.maxX - 38,
             y: titleBarFrame.minY + 6,
             width: 30,
             height: 14
         )
+        card.metaLayer.foregroundColor = themePalette.cardSecondaryText.cgColor
         card.stateLayer.frame = CGRect(
             x: thumbnailFrame.maxX - 86,
             y: thumbnailFrame.minY + 6,
             width: 78,
             height: 14
         )
+        card.stateLayer.foregroundColor = themePalette.cardSecondaryText.cgColor
         layoutCloseButton(
             card.closeButton,
             target: .window(
@@ -2458,7 +5930,7 @@
                 windowIndex: card.item.windowIndex,
                 windowID: card.item.window.id
             ),
-            visible: isHovered,
+            visible: isHovered && shortcutFilterState != .dimmed,
             anchorTopRight: CGPoint(x: bounds.maxX - 12, y: bounds.maxY - 12)
         )
         card.shineLayer.frame = CGRect(
@@ -2467,43 +5939,72 @@
             width: max(36, min(96, bounds.width * 0.24)),
             height: bounds.height
         )
+        card.shineLayer.colors = [
+            NSColor.white.withAlphaComponent(0.00).cgColor,
+            themePalette.shinePeak.cgColor,
+            NSColor.white.withAlphaComponent(0.00).cgColor
+        ]
     }
 
-    private func applyWaterfallCardVisualState(_ card: WaterfallCardLayers, selected: Bool, hovered: Bool) {
-        let isSpaceFocused = card.item.primarySpaceID == activeSpaceFocusID
+    private func applyWaterfallCardVisualState(
+        _ card: WaterfallCardLayers,
+        selected: Bool,
+        hovered: Bool,
+        appLinked: Bool,
+        shortcutFilterState: WindowShortcutFilterState
+    ) {
+        let isSpaceFocused = isWaterfallCardSpaceFocused(card)
+        let isShortcutDimmed = shortcutFilterState == .dimmed
         card.containerLayer.backgroundColor = (selected
-            ? NSColor.windowBackgroundColor.withAlphaComponent(0.94)
+            ? themePalette.cardSelectedBackground
             : hovered
                 ? accentTintedWindowBackground(fraction: 0.09, alpha: 0.95)
+                : appLinked
+                    ? accentTintedWindowBackground(fraction: 0.08, alpha: 0.93)
                 : isSpaceFocused
                     ? accentTintedWindowBackground(fraction: 0.10, alpha: 0.94)
-                : NSColor.windowBackgroundColor.withAlphaComponent(0.82)
+                : themePalette.cardBackground
         ).cgColor
+        card.containerLayer.opacity = isShortcutDimmed ? windowShortcutFilterDimOpacity : 1
         card.containerLayer.borderColor = (selected
             ? NSColor.controlAccentColor.withAlphaComponent(0.52)
             : hovered
                 ? NSColor.controlAccentColor.withAlphaComponent(0.44)
+                : appLinked
+                    ? NSColor.controlAccentColor.withAlphaComponent(0.38)
                 : isSpaceFocused
                     ? NSColor.controlAccentColor.withAlphaComponent(0.42)
                 : NSColor.separatorColor.withAlphaComponent(0.28)
         ).cgColor
-        card.containerLayer.borderWidth = (selected || hovered || isSpaceFocused) ? 1.5 : 1
+        card.containerLayer.borderWidth = (selected || hovered || appLinked || isSpaceFocused) ? 1.5 : 1
         card.containerLayer.shadowColor = NSColor.black.cgColor
-        card.containerLayer.shadowOpacity = selected ? 0.24 : hovered ? 0.14 : isSpaceFocused ? 0.20 : 0
-        card.containerLayer.shadowRadius = selected ? 22 : hovered ? 17 : isSpaceFocused ? 24 : 0
+        let darkShadowBoost: Float = resolvedTheme == .dark ? 0.08 : 0
+        let baseShadowOpacity: Float = selected
+            ? 0.24 + darkShadowBoost
+            : hovered
+                ? 0.14 + darkShadowBoost
+                : appLinked
+                    ? 0.16 + darkShadowBoost
+                    : isSpaceFocused
+                        ? 0.20 + darkShadowBoost
+                        : 0
+        card.containerLayer.shadowOpacity = isShortcutDimmed ? min(baseShadowOpacity, 0.03) : baseShadowOpacity
+        card.containerLayer.shadowRadius = selected ? 22 : hovered ? 17 : appLinked ? 18 : isSpaceFocused ? 24 : 0
         card.containerLayer.shadowOffset = selected
             ? CGSize(width: 0, height: -6)
             : hovered
                 ? CGSize(width: 0, height: -2.5)
+                : appLinked
+                    ? CGSize(width: 0, height: -3)
                 : isSpaceFocused
                     ? CGSize(width: 0, height: -5)
                     : .zero
-        card.containerLayer.zPosition = selected ? 20 : hovered ? 10 : isSpaceFocused ? 8 : 0
-        let focusedScale: CGFloat = selected ? 1.015 : isSpaceFocused ? 1.012 : 1.008
-        card.containerLayer.transform = (selected || hovered || isSpaceFocused)
+        card.containerLayer.zPosition = selected ? 20 : hovered ? 12 : appLinked ? 10 : isSpaceFocused ? 8 : 0
+        let focusedScale: CGFloat = selected ? WaterfallMetrics.selectedCardScale : isSpaceFocused ? 1.012 : 1.008
+        card.containerLayer.transform = (!isShortcutDimmed && (selected || hovered || isSpaceFocused))
             ? CATransform3DMakeScale(focusedScale, focusedScale, 1)
             : CATransform3DIdentity
-        card.containerLayer.shadowPath = (selected || hovered || isSpaceFocused)
+        card.containerLayer.shadowPath = (!isShortcutDimmed && (selected || hovered || appLinked || isSpaceFocused))
             ? CGPath(
                 roundedRect: card.containerLayer.bounds,
                 cornerWidth: card.containerLayer.cornerRadius,
@@ -2511,10 +6012,15 @@
                 transform: nil
             )
             : nil
-        card.titleBarLayer.backgroundColor = NSColor.clear.cgColor
+        card.titleBarLayer.backgroundColor = (selected
+            ? spaceLaneOccupiedColor.withAlphaComponent(0.22)
+            : appLinked
+                ? spaceLaneOccupiedColor.withAlphaComponent(0.18)
+                : NSColor.clear
+        ).cgColor
         card.titleBarLayer.borderColor = NSColor.clear.cgColor
         card.titleBarLayer.borderWidth = 0
-        card.shineLayer.opacity = selected ? 1 : 0
+        card.shineLayer.opacity = (!isShortcutDimmed && selected) ? 1 : 0
     }
 
     private func layoutCloseButton(
@@ -2527,13 +6033,14 @@
         let size: CGFloat = isButtonHovered ? 24 : 18
         let buttonFill = isButtonHovered
             ? NSColor.systemRed.withAlphaComponent(0.94)
-            : NSColor.labelColor.withAlphaComponent(0.24)
+            : NSColor.white.withAlphaComponent(0.34)
         let buttonStroke = isButtonHovered
             ? NSColor.white.withAlphaComponent(0.76)
-            : NSColor.white.withAlphaComponent(0.52)
+            : NSColor.white.withAlphaComponent(0.46)
         let glyphStroke = isButtonHovered
             ? NSColor.white
-            : NSColor.secondaryLabelColor.withAlphaComponent(0.92)
+            : NSColor.white.withAlphaComponent(0.88)
+
         button.containerLayer.frame = CGRect(
             x: anchorTopRight.x - size / 2,
             y: anchorTopRight.y - size / 2,
@@ -2545,10 +6052,10 @@
         button.containerLayer.borderColor = buttonStroke.cgColor
         button.containerLayer.opacity = visible ? 1 : 0
         button.containerLayer.zPosition = isButtonHovered ? 80 : 60
-        button.containerLayer.shadowOpacity = visible ? (isButtonHovered ? 0.22 : 0.07) : 0
+        button.containerLayer.shadowOpacity = visible ? (isButtonHovered ? 0.22 : 0.04) : 0
         button.containerLayer.shadowRadius = isButtonHovered ? 9 : 5
         button.glyphLayer.frame = CGRect(x: 0, y: 0, width: size, height: size)
-        button.glyphLayer.lineWidth = isButtonHovered ? 2.1 : 1.7
+        button.glyphLayer.lineWidth = isButtonHovered ? 2.1 : 1.45
         button.glyphLayer.strokeColor = glyphStroke.cgColor
         button.glyphLayer.path = closeGlyphPath(size: size, hovered: isButtonHovered)
     }
@@ -2616,9 +6123,16 @@
         )
         layers.backgroundLayer.frame = layers.containerLayer.bounds
         layers.backgroundLayer.path = bubblePath
+        layers.backgroundLayer.fillColor = themePalette.closeFeedbackBackground.withAlphaComponent(resolvedTheme == .dark ? 0.98 : 0.985).cgColor
+        layers.backgroundLayer.strokeColor = themePalette.closeFeedbackBorder.withAlphaComponent(resolvedTheme == .dark ? 0.78 : 1).cgColor
         layers.containerLayer.shadowPath = bubblePath
         layers.titleLayer.string = confirmationTitle(for: request)
         layers.messageLayer.string = confirmationMessage(for: request)
+        layers.titleLayer.foregroundColor = (resolvedTheme == .dark
+            ? NSColor.white.withAlphaComponent(0.92)
+            : NSColor.labelColor
+        ).cgColor
+        layers.messageLayer.foregroundColor = themePalette.closeFeedbackText.cgColor
         layers.titleLayer.frame = CGRect(x: contentFrame.minX + 22, y: height - 48, width: contentFrame.width - 44, height: 22)
         layers.messageLayer.frame = CGRect(x: contentFrame.minX + 22, y: height - 78, width: contentFrame.width - 44, height: 21)
 
@@ -2629,16 +6143,100 @@
         ).cgColor
         layers.checkboxLayer.borderColor = (pendingCloseOptOut
             ? NSColor.controlAccentColor.withAlphaComponent(0.95)
-            : NSColor.separatorColor.withAlphaComponent(0.48)
+            : themePalette.closeFeedbackBorder.withAlphaComponent(resolvedTheme == .dark ? 0.80 : 0.48)
         ).cgColor
         layers.checkboxMarkLayer.string = pendingCloseOptOut ? "✓" : ""
         layers.checkboxMarkLayer.frame = CGRect(x: 0, y: 1, width: 18, height: 16)
+        layers.checkboxLabelLayer.foregroundColor = themePalette.closeFeedbackText.cgColor
         layers.checkboxLabelLayer.frame = CGRect(x: contentFrame.minX + 48, y: 80, width: contentFrame.width - 70, height: 19)
 
+        layers.cancelButtonLayer.backgroundColor = (resolvedTheme == .dark
+            ? NSColor.white.withAlphaComponent(0.10)
+            : NSColor.systemFill.withAlphaComponent(0.16)
+        ).cgColor
+        layers.cancelButtonLayer.borderColor = themePalette.closeFeedbackBorder.withAlphaComponent(resolvedTheme == .dark ? 0.70 : 0.22).cgColor
+        layers.cancelButtonTextLayer.foregroundColor = (resolvedTheme == .dark
+            ? NSColor.white.withAlphaComponent(0.86)
+            : NSColor.labelColor
+        ).cgColor
         layers.cancelButtonLayer.frame = CGRect(x: contentFrame.maxX - 164, y: 22, width: 74, height: 32)
         layers.cancelButtonTextLayer.frame = layers.cancelButtonLayer.bounds.insetBy(dx: 0, dy: 7)
         layers.confirmButtonLayer.frame = CGRect(x: contentFrame.maxX - 78, y: 22, width: 56, height: 32)
         layers.confirmButtonTextLayer.frame = layers.confirmButtonLayer.bounds.insetBy(dx: 0, dy: 7)
+    }
+
+    private func setCloseFeedback(_ feedback: CloseFeedback, autoHideAfter delay: TimeInterval?) {
+        closeFeedbackHideTask?.cancel()
+        closeFeedback = feedback
+        closeFeedbackLayer.isHidden = false
+        closeFeedbackLayer.opacity = 1
+        closeFeedbackTextLayer.string = feedback.message
+        switch feedback.kind {
+        case .progress:
+            closeFeedbackLayer.backgroundColor = themePalette.closeFeedbackBackground.cgColor
+            closeFeedbackLayer.borderColor = themePalette.closeFeedbackBorder.cgColor
+            closeFeedbackTextLayer.foregroundColor = themePalette.closeFeedbackText.cgColor
+        case .failure:
+            closeFeedbackLayer.backgroundColor = NSColor.systemRed.withAlphaComponent(0.10).cgColor
+            closeFeedbackLayer.borderColor = NSColor.systemRed.withAlphaComponent(0.32).cgColor
+            closeFeedbackTextLayer.foregroundColor = NSColor.systemRed.withAlphaComponent(0.95).cgColor
+        }
+        needsLayout = true
+
+        guard let delay else {
+            closeFeedbackHideTask = nil
+            return
+        }
+
+        closeFeedbackHideTask = Task { @MainActor [weak self] in
+            try? await Task.sleep(nanoseconds: UInt64(delay * 1_000_000_000))
+            guard !Task.isCancelled,
+                  let self,
+                  self.closeFeedback == feedback
+            else {
+                return
+            }
+            self.clearCloseFeedback()
+        }
+    }
+
+    private func layoutCloseFeedback() {
+        guard let feedback = closeFeedback else {
+            closeFeedbackLayer.isHidden = true
+            closeFeedbackLayer.opacity = 0
+            return
+        }
+
+        closeFeedbackLayer.isHidden = false
+        closeFeedbackLayer.opacity = 1
+        let font = NSFont.systemFont(
+            ofSize: 13,
+            weight: feedback.kind == .failure ? .medium : .regular
+        )
+        closeFeedbackTextLayer.font = font
+        closeFeedbackTextLayer.fontSize = 13
+        let textWidth = (feedback.message as NSString).size(
+            withAttributes: [.font: font]
+        ).width
+        let maxWidth = max(180, glassLayer.bounds.width - 48)
+        let width = min(max(180, textWidth + 34), min(460, maxWidth))
+        let height: CGFloat = 34
+        let x = max(24, (glassLayer.bounds.width - width) / 2)
+        let preferredY = waterfallLayer.frame.maxY - height - 14
+        let y = min(
+            max(16, preferredY),
+            max(16, glassLayer.bounds.height - height - 16)
+        )
+
+        closeFeedbackLayer.frame = CGRect(x: x, y: y, width: width, height: height)
+        closeFeedbackLayer.cornerRadius = height / 2
+        closeFeedbackLayer.shadowPath = CGPath(
+            roundedRect: closeFeedbackLayer.bounds,
+            cornerWidth: closeFeedbackLayer.cornerRadius,
+            cornerHeight: closeFeedbackLayer.cornerRadius,
+            transform: nil
+        )
+        closeFeedbackTextLayer.frame = closeFeedbackLayer.bounds.insetBy(dx: 17, dy: 8)
     }
 
     private func closeConfirmationBubblePath(
@@ -2726,18 +6324,23 @@
         }
 
         pendingCloseTarget = nil
+        pendingCloseRequest = nil
         pendingCloseOptOut = false
         closeConfirmationLayers.containerLayer.isHidden = true
         closeConfirmationArrowEdge = nil
-        if pendingCloseOptOut {
-            onCloseConfirmationDisabled?()
-        }
         onRequestClose?(request)
     }
 
     private func beginCloseConfirmation(for target: CloseTarget) {
         if closeConfirmationRequired {
+            guard let request = closeRequest(for: target) else {
+                DevelopmentDiagnostics.log("quickSwitch.view.closeConfirmation.missingRequest", [
+                    "targetKind": target.kindDescription
+                ])
+                return
+            }
             pendingCloseTarget = target
+            pendingCloseRequest = request
             pendingCloseOptOut = false
             DevelopmentDiagnostics.log("quickSwitch.view.closeConfirmation.show", [
                 "targetKind": target.kindDescription
@@ -2750,23 +6353,30 @@
     }
 
     private func confirmPendingClose() {
-        guard let target = pendingCloseTarget else { return }
+        guard let target = pendingCloseTarget,
+              let request = pendingCloseRequest
+        else { return }
         let shouldDisableConfirmation = pendingCloseOptOut
         pendingCloseTarget = nil
+        pendingCloseRequest = nil
         pendingCloseOptOut = false
         closeConfirmationLayers.containerLayer.isHidden = true
         closeConfirmationArrowEdge = nil
-        if shouldDisableConfirmation {
+        if shouldDisableConfirmation && closeConfirmationRequired {
+            closeConfirmationRequired = false
             onCloseConfirmationDisabled?()
         }
-        if let request = closeRequest(for: target) {
-            onRequestClose?(request)
-        }
+        DevelopmentDiagnostics.log("quickSwitch.view.closeConfirmation.confirm", [
+            "targetKind": target.kindDescription,
+            "disableFutureConfirmation": shouldDisableConfirmation
+        ])
+        onRequestClose?(request)
     }
 
     private func cancelPendingClose() {
         DevelopmentDiagnostics.log("quickSwitch.view.closeConfirmation.cancel")
         pendingCloseTarget = nil
+        pendingCloseRequest = nil
         pendingCloseOptOut = false
         closeConfirmationLayers.containerLayer.isHidden = true
         closeConfirmationArrowEdge = nil
@@ -2774,7 +6384,15 @@
     }
 
     private func toggleCloseConfirmationOptOut() {
+        if pendingCloseOptOut && !closeConfirmationRequired {
+            return
+        }
         pendingCloseOptOut.toggle()
+        if pendingCloseOptOut {
+            closeConfirmationRequired = false
+            onCloseConfirmationDisabled?()
+            DevelopmentDiagnostics.log("quickSwitch.view.closeConfirmation.optOutPersisted")
+        }
         needsLayout = true
     }
 
@@ -2843,11 +6461,7 @@
     }
 
     private func appShelfCloseButtonTarget(at windowLocation: NSPoint) -> CloseTarget? {
-        let locationInView = convert(windowLocation, from: nil)
-        let locationInAppShelfContent = CGPoint(
-            x: locationInView.x - glassLayer.frame.minX - shelfLayer.frame.minX - appShelfContentLayer.frame.minX,
-            y: locationInView.y - glassLayer.frame.minY - shelfLayer.frame.minY - appShelfContentLayer.frame.minY
-        )
+        let locationInAppShelfContent = appShelfContentLocation(at: windowLocation)
 
         for item in appShelfItems {
             let target = CloseTarget.app(appGroupIndex: item.item.appGroupIndex)
@@ -2855,36 +6469,59 @@
                   canClose(app: item.item.app)
             else { continue }
 
+            let itemFrame = interactiveFrame(for: item.containerLayer)
+            let closeFrame = interactiveFrame(for: item.closeButton.containerLayer)
             let locationInItem = CGPoint(
-                x: locationInAppShelfContent.x - item.containerLayer.frame.minX,
-                y: locationInAppShelfContent.y - item.containerLayer.frame.minY
+                x: locationInAppShelfContent.x - itemFrame.minX,
+                y: locationInAppShelfContent.y - itemFrame.minY
             )
-            if item.closeButton.containerLayer.frame.insetBy(dx: -8, dy: -8).contains(locationInItem) {
+            if appShelfCloseHitFrame(for: closeFrame).contains(locationInItem) {
                 return target
             }
         }
         return nil
     }
 
+    private func appShelfCloseHitFrame(for closeFrame: CGRect) -> CGRect {
+        closeFrame.insetBy(
+            dx: -AppShelfMetrics.closeButtonHitOutset,
+            dy: -AppShelfMetrics.closeButtonHitOutset
+        )
+    }
+
     private func waterfallCloseButtonTarget(at windowLocation: NSPoint) -> CloseTarget? {
         let locationInView = convert(windowLocation, from: nil)
+        let glassFrame = interactiveFrame(for: glassLayer)
+        let waterfallFrame = interactiveFrame(for: waterfallLayer)
+        let waterfallContentFrame = interactiveFrame(for: waterfallContentLayer)
         let locationInWaterfallContent = CGPoint(
-            x: locationInView.x - glassLayer.frame.minX - waterfallLayer.frame.minX - waterfallContentLayer.frame.minX,
-            y: locationInView.y - glassLayer.frame.minY - waterfallLayer.frame.minY - waterfallContentLayer.frame.minY
+            x: locationInView.x - glassFrame.minX - waterfallFrame.minX - waterfallContentFrame.minX,
+            y: locationInView.y - glassFrame.minY - waterfallFrame.minY - waterfallContentFrame.minY
         )
 
-        for column in waterfallColumns where column.containerLayer.frame.contains(locationInWaterfallContent) {
+        for column in waterfallColumns where interactiveFrame(for: column.containerLayer).contains(locationInWaterfallContent) {
+            let columnFrame = interactiveFrame(for: column.containerLayer)
+            let cardsClipFrame = interactiveFrame(for: column.cardsClipLayer)
             let locationInColumn = CGPoint(
-                x: locationInWaterfallContent.x - column.containerLayer.frame.minX,
-                y: locationInWaterfallContent.y - column.containerLayer.frame.minY
+                x: locationInWaterfallContent.x - columnFrame.minX,
+                y: locationInWaterfallContent.y - columnFrame.minY
             )
-            for card in column.cards where card.containerLayer.frame.contains(locationInColumn) {
+            guard cardsClipFrame.contains(locationInColumn) else {
+                continue
+            }
+            let locationInCardsClip = CGPoint(
+                x: locationInColumn.x - cardsClipFrame.minX,
+                y: locationInColumn.y - cardsClipFrame.minY
+            )
+            for card in column.cards where interactiveFrame(for: card.containerLayer).contains(locationInCardsClip) {
                 guard card.closeButton.containerLayer.opacity > 0 else { continue }
+                let cardFrame = interactiveFrame(for: card.containerLayer)
+                let closeFrame = interactiveFrame(for: card.closeButton.containerLayer)
                 let locationInCard = CGPoint(
-                    x: locationInColumn.x - card.containerLayer.frame.minX,
-                    y: locationInColumn.y - card.containerLayer.frame.minY
+                    x: locationInCardsClip.x - cardFrame.minX,
+                    y: locationInCardsClip.y - cardFrame.minY
                 )
-                if card.closeButton.containerLayer.frame.insetBy(dx: -8, dy: -8).contains(locationInCard) {
+                if closeFrame.insetBy(dx: -8, dy: -8).contains(locationInCard) {
                     return .window(
                         appGroupIndex: card.item.appGroupIndex,
                         windowIndex: card.item.windowIndex,
@@ -2924,11 +6561,13 @@
                 x: waterfallLayer.frame.minX
                     + waterfallContentLayer.frame.minX
                     + column.containerLayer.frame.minX
+                    + column.cardsClipLayer.frame.minX
                     + card.containerLayer.frame.minX
                     + card.closeButton.containerLayer.frame.midX,
                 y: waterfallLayer.frame.minY
                     + waterfallContentLayer.frame.minY
                     + column.containerLayer.frame.minY
+                    + column.cardsClipLayer.frame.minY
                     + card.containerLayer.frame.minY
                     + card.closeButton.containerLayer.frame.midY
             )
@@ -2936,9 +6575,39 @@
     }
 
     private func accentTintedWindowBackground(fraction: CGFloat, alpha: CGFloat) -> NSColor {
-        let color = NSColor.windowBackgroundColor.blended(withFraction: fraction, of: NSColor.controlAccentColor)
-            ?? NSColor.windowBackgroundColor
+        let baseColor = resolvedTheme == .dark ? themePalette.cardBackground : NSColor.windowBackgroundColor
+        let color = baseColor.blended(withFraction: fraction, of: NSColor.controlAccentColor)
+            ?? baseColor
         return color.withAlphaComponent(alpha)
+    }
+
+    private func isWaterfallCardSpaceFocused(_ card: WaterfallCardLayers) -> Bool {
+        guard let activeSpaceFocusID else { return false }
+        return card.item.primarySpaceID == activeSpaceFocusID
+    }
+
+    private func isWaterfallCardAppLinked(_ card: WaterfallCardLayers) -> Bool {
+        guard card.item.appGroupIndex == appIconHoverLinkedAppGroupIndex else { return false }
+
+        if isHorizontalMasonryMode {
+            return true
+        }
+
+        if keyboardFocusedWindowID != nil {
+            return false
+        }
+
+        return waterfallColumns
+            .first(where: { $0.column.appGroupIndex == card.item.appGroupIndex })?
+            .cards
+            .sorted { lhs, rhs in
+                if lhs.item.windowIndex != rhs.item.windowIndex {
+                    return lhs.item.windowIndex < rhs.item.windowIndex
+                }
+                return lhs.item.window.id < rhs.item.window.id
+            }
+            .first?
+            .item.window.id == card.item.window.id
     }
 
     private func waterfallColumnWidth() -> CGFloat {
@@ -2947,7 +6616,7 @@
         let visibleColumns = min(4, max(1, waterfallColumns.count))
         let fittingWidth = (
             waterfallLayer.bounds.width
-                - WaterfallMetrics.columnPadding * 2
+                - WaterfallMetrics.contentHorizontalPadding * 2
                 - CGFloat(max(0, visibleColumns - 1)) * WaterfallMetrics.gap
         ) / CGFloat(visibleColumns)
         return max(
@@ -2956,15 +6625,109 @@
         )
     }
 
+    private var isHorizontalMasonryMode: Bool {
+        waterfallViewMode == .horizontalMasonry
+    }
+
+    private var resolvedTheme: QuickSwitchResolvedTheme {
+        themePreference == .dark ? .dark : .light
+    }
+
+    private var themePalette: QuickSwitchThemePalette {
+        QuickSwitchThemePalette.palette(for: resolvedTheme)
+    }
+
+    private var darkBackdropAmbientLayers: [CAGradientLayer] {
+        [darkAmbientLeftLayer, darkAmbientCenterLayer, darkAmbientRightLayer]
+    }
+
+    private static func normalizedQuickSwitchTheme(_ theme: ThemePreference) -> ThemePreference {
+        theme == .dark ? .dark : .light
+    }
+
+    private var nextThemePreference: ThemePreference {
+        resolvedTheme == .dark ? .light : .dark
+    }
+
+    private var nextWaterfallViewMode: QuickSwitchWaterfallViewMode {
+        isHorizontalMasonryMode ? .verticalColumns : .horizontalMasonry
+    }
+
+    private var viewModeToggleBlueColor: NSColor {
+        NSColor(deviceRed: 135.0 / 255.0, green: 200.0 / 255.0, blue: 1, alpha: 1)
+    }
+
+    private var themeToggleIdleBackgroundColor: NSColor {
+        toggleIdleBackgroundColor(hovered: isThemeToggleButtonHovered)
+    }
+
+    private func toggleIdleBackgroundColor(hovered: Bool) -> NSColor {
+        switch resolvedTheme {
+        case .light:
+            return NSColor.windowBackgroundColor.withAlphaComponent(hovered ? 0.76 : 0.58)
+        case .dark:
+            return NSColor(calibratedRed: 24 / 255, green: 34 / 255, blue: 54 / 255, alpha: hovered ? 0.76 : 0.58)
+        }
+    }
+
+    private var viewModeToggleVisualState: ViewModeToggleVisualState {
+        if isHorizontalMasonryMode {
+            return isViewModeToggleButtonHovered ? .verticalAvailable : .horizontalSelected
+        }
+        return isViewModeToggleButtonHovered ? .horizontalAvailable : .verticalSelected
+    }
+
+    private func viewModeToggleVisualStateIsSelected(_ state: ViewModeToggleVisualState) -> Bool {
+        switch state {
+        case .horizontalSelected, .verticalSelected:
+            return true
+        case .horizontalAvailable, .verticalAvailable:
+            return false
+        }
+    }
+
+    private var viewModeToggleIconKind: String {
+        viewModeToggleVisualState.rawValue
+    }
+
+    private var viewModeToggleAccessibilityLabel: String {
+        switch nextWaterfallViewMode {
+        case .verticalColumns:
+            return "切换到纵栏瀑布"
+        case .horizontalMasonry:
+            return "切换到横栏瀑布"
+        }
+    }
+
+    private var themeToggleAccessibilityLabel: String {
+        switch nextThemePreference {
+        case .dark:
+            return "切换到深色皮肤"
+        case .light, .system:
+            return "切换到浅色皮肤"
+        }
+    }
+
     private var waterfallMaxScrollOffset: CGFloat {
-        max(0, waterfallContentWidth - waterfallLayer.bounds.width)
+        guard !isHorizontalMasonryMode else { return 0 }
+        return max(0, waterfallContentWidth - waterfallLayer.bounds.width)
     }
 
     private func clampedWaterfallOffset(_ offset: CGFloat) -> CGFloat {
         min(max(0, offset), waterfallMaxScrollOffset)
     }
 
+    private var horizontalMasonryMaxScrollOffset: CGFloat {
+        max(0, horizontalMasonryContentHeight - waterfallLayer.bounds.height)
+    }
+
+    private func clampedHorizontalMasonryOffset(_ offset: CGFloat) -> CGFloat {
+        min(max(0, offset), horizontalMasonryMaxScrollOffset)
+    }
+
     private func waterfallMaxVerticalScrollOffset(for appGroupIndex: Int) -> CGFloat {
+        guard !isHorizontalMasonryMode else { return 0 }
+
         guard
             let column = waterfallColumns.first(where: { $0.column.appGroupIndex == appGroupIndex })
         else {
@@ -2975,11 +6738,11 @@
             1,
             waterfallLayer.bounds.height
                 - WaterfallMetrics.headerHeight
-                - WaterfallMetrics.columnPadding * 2
+                - WaterfallMetrics.columnVerticalPadding * 2
         )
         let contentHeight = CGFloat(column.cards.count) * WaterfallMetrics.cardHeight
             + CGFloat(max(0, column.cards.count - 1)) * WaterfallMetrics.cardGap
-        return max(0, contentHeight - visibleHeight)
+        return max(0, contentHeight - visibleHeight + WaterfallMetrics.selectedCardScaleOverflow * 2)
     }
 
     private func clampedWaterfallColumnOffset(_ offset: CGFloat, appGroupIndex: Int) -> CGFloat {
@@ -2987,7 +6750,130 @@
     }
 
     private func waterfallMetaText(for card: QuickSwitchWindowCardViewModel) -> String {
-        card.primarySpaceLabel ?? "No Space"
+        windowShortcutCode(for: card) ?? ""
+    }
+
+    private func windowShortcutCode(for card: QuickSwitchWindowCardViewModel) -> String? {
+        guard let appOrdinal = appShelfItems.firstIndex(where: { $0.item.appGroupIndex == card.appGroupIndex }),
+              let appSymbol = singleIndexSymbol(forOrdinal: appOrdinal),
+              let windowSymbol = singleIndexSymbol(forOrdinal: card.windowIndex)
+        else {
+            return nil
+        }
+        return "\(appSymbol)\(windowSymbol)"
+    }
+
+    private func singleIndexSymbol(forOrdinal ordinal: Int) -> String? {
+        guard ordinal >= 0,
+              ordinal < Self.appShelfIndexSymbols.count
+        else {
+            return nil
+        }
+        return Self.appShelfIndexSymbols[ordinal]
+    }
+
+    private var visibleWaterfallCards: [WaterfallCardLayers] {
+        waterfallColumns.flatMap(\.cards)
+    }
+
+    private func singleVisibleWaterfallCard(appGroupIndex: Int) -> WaterfallCardLayers? {
+        let cards = visibleWaterfallCards.filter { $0.item.appGroupIndex == appGroupIndex }
+        return cards.count == 1 ? cards[0] : nil
+    }
+
+    private var windowShortcutFilterDimOpacity: Float {
+        resolvedTheme == .dark ? 0.44 : 0.38
+    }
+
+    private func windowShortcutFilterState(for card: WaterfallCardLayers) -> WindowShortcutFilterState {
+        switch windowShortcutFilterPhase {
+        case .appPending:
+            guard let pending = windowIndexKeyPending else { return .none }
+            return card.item.appGroupIndex == pending.appGroupIndex ? .matched : .dimmed
+        case .targetPreCommit:
+            guard let snapshot = lastWindowShortcutPreCommitFilterSnapshot else { return .none }
+            if card.item.window.id == snapshot.targetWindowID {
+                return .target
+            }
+            if snapshot.dimmedWindowIDs.contains(card.item.window.id) {
+                return .dimmed
+            }
+            if snapshot.matchedWindowIDs.contains(card.item.window.id) {
+                return .matched
+            }
+            return .none
+        case .none, .invalid, .expired:
+            return .none
+        }
+    }
+
+    private func makeWindowShortcutPreCommitFilterSnapshot(
+        target card: WaterfallCardLayers,
+        code: String
+    ) -> WindowShortcutPreCommitFilterSnapshot {
+        let targetWindowID = card.item.window.id
+        let allWindowIDs = visibleWaterfallCards.map { $0.item.window.id }
+        return WindowShortcutPreCommitFilterSnapshot(
+            targetCode: code,
+            targetWindowID: targetWindowID,
+            matchedWindowIDs: [targetWindowID],
+            dimmedWindowIDs: allWindowIDs.filter { $0 != targetWindowID }.sorted()
+        )
+    }
+
+    private func makeWindowShortcutFilterReport() -> WindowShortcutFilterReport {
+        switch windowShortcutFilterPhase {
+        case .appPending:
+            guard let pending = windowIndexKeyPending else {
+                return emptyWindowShortcutFilterReport(phase: .none)
+            }
+            let cards = visibleWaterfallCards
+            let matched = cards
+                .filter { $0.item.appGroupIndex == pending.appGroupIndex }
+                .map { $0.item.window.id }
+                .sorted()
+            let dimmed = cards
+                .filter { $0.item.appGroupIndex != pending.appGroupIndex }
+                .map { $0.item.window.id }
+                .sorted()
+            return WindowShortcutFilterReport(
+                active: true,
+                phase: .appPending,
+                pendingAppGroupIndex: pending.appGroupIndex,
+                prefix: pending.appSymbol,
+                matchedWindowIDs: matched,
+                dimmedWindowIDs: dimmed
+            )
+        case .targetPreCommit:
+            guard let snapshot = lastWindowShortcutPreCommitFilterSnapshot else {
+                return emptyWindowShortcutFilterReport(phase: .none)
+            }
+            return WindowShortcutFilterReport(
+                active: true,
+                phase: .targetPreCommit,
+                pendingAppGroupIndex: nil,
+                prefix: snapshot.targetCode,
+                matchedWindowIDs: snapshot.matchedWindowIDs,
+                dimmedWindowIDs: snapshot.dimmedWindowIDs
+            )
+        case .invalid, .expired:
+            return emptyWindowShortcutFilterReport(phase: windowShortcutFilterPhase)
+        case .none:
+            return emptyWindowShortcutFilterReport(phase: .none)
+        }
+    }
+
+    private func emptyWindowShortcutFilterReport(
+        phase: WindowShortcutFilterPhase
+    ) -> WindowShortcutFilterReport {
+        WindowShortcutFilterReport(
+            active: false,
+            phase: phase,
+            pendingAppGroupIndex: nil,
+            prefix: nil,
+            matchedWindowIDs: [],
+            dimmedWindowIDs: []
+        )
     }
 
     private func waterfallStateText(for card: QuickSwitchWindowCardViewModel) -> String {
@@ -3005,15 +6891,51 @@
         return states.joined(separator: " / ")
     }
 
-    private func spaceColor(for space: QuickSwitchSpaceViewModel) -> NSColor {
-        if space.isCurrent {
-            return NSColor.windowBackgroundColor.withAlphaComponent(0.76)
-        }
-        if space.windowCount > 0 {
-            return NSColor.controlBackgroundColor.withAlphaComponent(0.56)
+    private var spaceLaneOccupiedColor: NSColor {
+        if resolvedTheme == .dark {
+            return NSColor(calibratedRed: 10 / 255, green: 132 / 255, blue: 1, alpha: 1)
         }
 
-        return NSColor.controlBackgroundColor.withAlphaComponent(0.26)
+        return NSColor(calibratedRed: 0, green: 122 / 255, blue: 1, alpha: 1)
+    }
+
+    private var spaceLaneLockedFillColor: NSColor {
+        if resolvedTheme == .dark {
+            return NSColor(calibratedRed: 58 / 255, green: 148 / 255, blue: 1, alpha: 0.86)
+        }
+
+        return NSColor(calibratedRed: 90 / 255, green: 171 / 255, blue: 1, alpha: 0.82)
+    }
+
+    private func spaceLaneIdleOccupiedGradientColors() -> [NSColor] {
+        if resolvedTheme == .dark {
+            let blue = NSColor(calibratedRed: 18 / 255, green: 42 / 255, blue: 70 / 255, alpha: 0.92)
+            let surface = NSColor(calibratedRed: 22 / 255, green: 34 / 255, blue: 50 / 255, alpha: 0.78)
+            return [blue, surface]
+        }
+
+        return [
+            NSColor(calibratedRed: 232 / 255, green: 246 / 255, blue: 1, alpha: 1),
+            NSColor.white
+        ]
+    }
+
+    private func applySpaceLaneGradientFill(to layer: CALayer, colors: [NSColor]) {
+        if let gradientLayer = layer as? CAGradientLayer {
+            gradientLayer.colors = colors.map(\.cgColor)
+            gradientLayer.locations = [0, 1].map(NSNumber.init(value:))
+            gradientLayer.startPoint = CGPoint(x: 0.5, y: 1.0)
+            gradientLayer.endPoint = CGPoint(x: 0.5, y: 0.0)
+        }
+        layer.backgroundColor = NSColor.clear.cgColor
+    }
+
+    private func applySpaceLaneSolidFill(to layer: CALayer, color: NSColor) {
+        if let gradientLayer = layer as? CAGradientLayer {
+            gradientLayer.colors = nil
+            gradientLayer.locations = nil
+        }
+        layer.backgroundColor = color.cgColor
     }
 
     private func makeFullscreenMarkerLayer(for space: QuickSwitchSpaceViewModel) -> CALayer? {
@@ -3179,10 +7101,9 @@
         return (0..<count).map { _ in
             let layer = CALayer()
             layer.cornerRadius = 3
-            layer.backgroundColor = (space.type == .fullscreen
-                ? NSColor.labelColor.withAlphaComponent(0.20)
-                : NSColor.labelColor.withAlphaComponent(0.18)
-            ).cgColor
+            layer.backgroundColor = spaceLaneOccupiedColor
+                .withAlphaComponent(space.isCurrent ? 0.72 : 0.58)
+                .cgColor
             return layer
         }
     }
@@ -3206,13 +7127,38 @@
         return identifiers.joined(separator: " ")
     }
 
-    private func layoutFullscreenMarkerLayer(_ layer: CALayer, in segmentBounds: CGRect) {
+    private func splitViewAppNames(for space: QuickSwitchSpaceViewModel) -> [String] {
+        guard space.type == .fullscreen else { return [] }
+
+        let names = space.splitViewAppNames
+            .prefix(2)
+            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            .filter { !$0.isEmpty }
+
+        guard names.count >= 2 else { return [] }
+        return names
+    }
+
+    private func layoutFullscreenMarkerLayer(
+        _ layer: CALayer,
+        in segmentBounds: CGRect,
+        isSplitView: Bool = false
+    ) {
         let markerFrame = fullscreenMarkerFrame(in: segmentBounds)
         layer.frame = markerFrame
 
         guard let shapeLayer = layer as? CAShapeLayer else { return }
 
         let bounds = shapeLayer.bounds
+        if isSplitView {
+            let path = CGMutablePath()
+            path.move(to: CGPoint(x: bounds.midX, y: bounds.minY))
+            path.addLine(to: CGPoint(x: bounds.midX, y: bounds.maxY))
+            shapeLayer.path = path
+            shapeLayer.lineCap = .butt
+            return
+        }
+
         let cornerLength = min(12, max(7, min(bounds.width, bounds.height) * 0.28))
         let path = CGMutablePath()
 
@@ -3233,14 +7179,22 @@
         path.addLine(to: CGPoint(x: 0, y: bounds.maxY - cornerLength))
 
         shapeLayer.path = path
+        shapeLayer.lineCap = .round
     }
 
     private func fullscreenMarkerFrame(in segmentBounds: CGRect) -> CGRect {
-        CGRect(
+        let topReserved: CGFloat = 32
+        let bottomReserved: CGFloat = 16
+        let availableHeight = max(20, segmentBounds.height - topReserved - bottomReserved)
+        let markerHeight = min(30, max(20, availableHeight))
+        let markerCenterY = bottomReserved + availableHeight * 0.5
+        let markerY = max(8, min(segmentBounds.height - topReserved - markerHeight, markerCenterY - markerHeight * 0.5))
+
+        return CGRect(
             x: 10,
-            y: 30,
+            y: markerY,
             width: max(1, segmentBounds.width - 20),
-            height: max(1, segmentBounds.height - 58)
+            height: markerHeight
         )
     }
 
@@ -3258,6 +7212,7 @@
     private func appShelfItemReports() -> [[String: Any]] {
         appShelfItems.enumerated().map { index, item in
             let visibleFrame = item.containerLayer.frame.offsetBy(dx: appShelfContentLayer.frame.minX, dy: 0)
+            let magneticState = appShelfMagneticState(for: item)
             return [
                 "index": index,
                 "name": item.item.app.name,
@@ -3268,21 +7223,42 @@
                 "isSelected": item.item.appGroupIndex == effectiveSelection?.appGroupIndex,
                 "isHovered": item.item.appGroupIndex == effectiveHoveredAppGroupIndex,
                 "isSpaceFocused": spaceFocusWindowCount(for: item.item.appGroupIndex) > 0,
+                "isMagneticNeighbor": magneticState.isNeighbor,
+                "magneticInfluence": Double(magneticState.influence),
+                "magneticLift": Double(magneticState.lift),
                 "visualStates": appShelfVisualStates(for: item),
                 "zPosition": Double(item.containerLayer.zPosition),
                 "hasMinimizedWindows": item.item.hasMinimizedWindows,
                 "hasFullscreenWindows": item.item.hasFullscreenWindows,
                 "frame": dictionary(from: item.containerLayer.frame),
                 "visibleFrame": dictionary(from: visibleFrame),
+                "containerBorderWidth": Double(item.containerLayer.borderWidth),
+                "containerBorderColor": colorDictionary(from: item.containerLayer.borderColor),
                 "iconFrame": dictionary(from: item.iconLayer.frame),
+                "iconBorderWidth": Double(item.iconLayer.borderWidth),
+                "iconBorderColor": colorDictionary(from: item.iconLayer.borderColor),
+                "backgroundFrame": dictionary(from: item.backgroundLayer.frame),
+                "backgroundColor": colorDictionary(from: item.backgroundLayer.backgroundColor),
+                "backgroundBorderWidth": Double(item.backgroundLayer.borderWidth),
+                "backgroundShadowOpacity": Double(item.backgroundLayer.shadowOpacity),
+                "backgroundShadowRadius": Double(item.backgroundLayer.shadowRadius),
+                "indexText": item.indexLayer.string ?? "",
+                "indexFrame": dictionary(from: item.indexLayer.frame),
+                "indexVisible": !item.indexLayer.isHidden && item.indexLayer.opacity > 0,
+                "indexFontSize": Double(item.indexLayer.fontSize),
+                "indexOpacity": Double(item.indexLayer.opacity),
+                "indexColor": colorDictionary(from: item.indexLayer.foregroundColor),
                 "labelFrame": dictionary(from: item.labelLayer.frame),
                 "labelTruncationMode": "middle",
                 "badgeVisible": !item.badgeLayer.isHidden,
                 "badgeText": item.badgeLayer.string ?? "",
                 "closeButtonVisible": item.closeButton.containerLayer.opacity > 0,
                 "closeButtonFrame": dictionary(from: item.closeButton.containerLayer.frame),
+                "closeButtonHitFrame": dictionary(from: appShelfCloseHitFrame(for: item.closeButton.containerLayer.frame)),
                 "closeButtonSize": Double(item.closeButton.containerLayer.bounds.width),
-                "closeButtonFillColor": colorDictionary(from: item.closeButton.containerLayer.backgroundColor)
+                "closeButtonFillColor": colorDictionary(from: item.closeButton.containerLayer.backgroundColor),
+                "closeButtonGlyphColor": colorDictionary(from: item.closeButton.glyphLayer.strokeColor),
+                "closeButtonGlyphLineWidth": Double(item.closeButton.glyphLayer.lineWidth)
             ] as [String: Any]
         }
     }
@@ -3290,13 +7266,18 @@
     private func appShelfVisualStates(for item: AppShelfItemLayers) -> [String] {
         var states: [String] = []
         let isSelected = item.item.appGroupIndex == effectiveSelection?.appGroupIndex
-        if shouldShowSelectedVisual(isSelected) {
+        let isHovered = item.item.appGroupIndex == effectiveHoveredAppGroupIndex
+        let magneticState = appShelfMagneticState(for: item)
+        if shouldShowSelectedVisual(isSelected: isSelected, isHovered: isHovered) {
             states.append("selected")
         } else if isSelected {
             states.append("selectedVisualSuppressed")
         }
-        if item.item.appGroupIndex == effectiveHoveredAppGroupIndex {
+        if isHovered {
             states.append("hover")
+        }
+        if magneticState.isNeighbor {
+            states.append("magneticNeighbor")
         }
         if spaceFocusWindowCount(for: item.item.appGroupIndex) > 0 {
             states.append("spaceFocused")
@@ -3308,21 +7289,56 @@
         return states
     }
 
+    private func waterfallColumnVisualStates(for column: WaterfallColumnLayers) -> [String] {
+        var states: [String] = []
+        if column.column.appGroupIndex == effectiveHoveredAppGroupIndex {
+            states.append("hover")
+        }
+        if spaceFocusWindowCount(for: column.column.appGroupIndex) > 0 {
+            states.append("spaceFocused")
+        }
+        return states
+    }
+
     private func waterfallColumnReports() -> [[String: Any]] {
         waterfallColumns.map { column in
             let visibleFrame = column.containerLayer.frame.offsetBy(dx: waterfallContentLayer.frame.minX, dy: 0)
             let appGroupIndex = column.column.appGroupIndex
+            let isHovered = appGroupIndex == effectiveHoveredAppGroupIndex
+            let firstCardFrame = column.cards.first?.containerLayer.frame
+            let visibleFirstCardFrame = firstCardFrame.map {
+                $0.offsetBy(dx: column.cardsClipLayer.frame.minX, dy: column.cardsClipLayer.frame.minY)
+            }
+            let headerToFirstCardGap = visibleFirstCardFrame.map {
+                column.headerLayer.frame.minY - $0.maxY
+            }
+            let topToFirstCardGap = visibleFirstCardFrame.map {
+                column.containerLayer.bounds.height - $0.maxY
+            }
 
             return [
                 "appGroupIndex": appGroupIndex,
                 "appName": column.column.app.name,
                 "bundleIdentifier": column.column.app.bundleIdentifier,
                 "windowCount": column.column.windows.count,
+                "isHovered": isHovered,
+                "visualStates": waterfallColumnVisualStates(for: column),
                 "spaceFocusWindowCount": spaceFocusWindowCount(for: appGroupIndex),
                 "isSpaceFocused": spaceFocusWindowCount(for: appGroupIndex) > 0,
                 "spaceFocusDirection": spaceFocusDirection(for: appGroupIndex),
                 "frame": dictionary(from: column.containerLayer.frame),
                 "visibleFrame": dictionary(from: visibleFrame),
+                "headerFrame": dictionary(from: column.headerLayer.frame),
+                "headerBackgroundColor": colorDictionary(from: column.headerLayer.backgroundColor),
+                "cardsClipFrame": dictionary(from: column.cardsClipLayer.frame),
+                "cardsClipMasksToBounds": column.cardsClipLayer.masksToBounds,
+                "headerToFirstCardGap": headerToFirstCardGap.map(Double.init) ?? NSNull(),
+                "topToFirstCardGap": topToFirstCardGap.map(Double.init) ?? NSNull(),
+                "appNameFrame": dictionary(from: column.appNameLayer.frame),
+                "appNameAlignment": column.appNameLayer.alignmentMode.rawValue,
+                "appNameColor": colorDictionary(from: column.appNameLayer.foregroundColor),
+                "countFrame": dictionary(from: column.countLayer.frame),
+                "countColor": colorDictionary(from: column.countLayer.foregroundColor),
                 "verticalScrollOffset": Double(waterfallColumnScrollOffsets[appGroupIndex] ?? 0),
                 "maxVerticalScrollOffset": Double(waterfallMaxVerticalScrollOffset(for: appGroupIndex)),
                 "cards": waterfallCardReports(for: column)
@@ -3380,10 +7396,14 @@
     private func waterfallCardReports(for column: WaterfallColumnLayers) -> [[String: Any]] {
         column.cards.map { card in
             let visibleFrame = card.containerLayer.frame.offsetBy(
-                dx: column.containerLayer.frame.minX + waterfallContentLayer.frame.minX,
-                dy: column.containerLayer.frame.minY
+                dx: column.containerLayer.frame.minX + column.cardsClipLayer.frame.minX + waterfallContentLayer.frame.minX,
+                dy: column.containerLayer.frame.minY + column.cardsClipLayer.frame.minY
             )
             let screenshotSource = screenshotSourcesByWindowID[card.item.window.id]
+            let shortcutFilterState = windowShortcutFilterState(for: card)
+            let shortcutFilterOpacity = shortcutFilterState == .dimmed
+                ? windowShortcutFilterDimOpacity
+                : Float(1)
 
             var report = [
                 "appGroupIndex": card.item.appGroupIndex,
@@ -3395,10 +7415,15 @@
                 "titleIsEmpty": card.item.window.title.isEmpty,
                 "primarySpaceID": card.item.primarySpaceID ?? NSNull(),
                 "primarySpaceLabel": card.item.primarySpaceLabel ?? NSNull(),
+                "windowShortcutCode": waterfallMetaText(for: card.item),
                 "isMinimized": card.item.window.isMinimized,
                 "isFullscreen": card.item.window.isFullscreen,
                 "identifierSource": "\(card.item.window.identifierSource)",
                 "isSelected": card.item.window.id == effectiveSelection?.windowID,
+                "isKeyboardFocused": card.item.window.id == keyboardFocusedWindowID,
+                "isHorizontalAppDefault": isHorizontalAppDefaultCard(card),
+                "windowShortcutFilterState": shortcutFilterState.rawValue,
+                "windowShortcutFilterOpacity": Double(shortcutFilterOpacity),
                 "visualStates": waterfallCardVisualStates(for: card),
                 "thumbnailStrategy": thumbnailStrategyString(for: card.item.window),
                 "screenshotSource": screenshotSourceString(screenshotSource, for: card.item.window),
@@ -3409,6 +7434,7 @@
                 "shadowRadius": Double(card.containerLayer.shadowRadius),
                 "thumbnailFrame": dictionary(from: card.thumbnailLayer.frame),
                 "titleBarFrame": dictionary(from: card.titleBarLayer.frame),
+                "titleBarBackgroundColor": colorDictionary(from: card.titleBarLayer.backgroundColor),
                 "titleBarBorderWidth": Double(card.titleBarLayer.borderWidth),
                 "titleFrame": dictionary(from: card.titleLayer.frame),
                 "metaFrame": dictionary(from: card.metaLayer.frame),
@@ -3418,8 +7444,11 @@
                 "closeButtonFrame": dictionary(from: card.closeButton.containerLayer.frame),
                 "closeButtonSize": Double(card.closeButton.containerLayer.bounds.width),
                 "closeButtonFillColor": colorDictionary(from: card.closeButton.containerLayer.backgroundColor),
+                "closeButtonGlyphColor": colorDictionary(from: card.closeButton.glyphLayer.strokeColor),
+                "closeButtonGlyphLineWidth": Double(card.closeButton.glyphLayer.lineWidth),
                 "shineVisible": card.shineLayer.opacity > 0,
                 "zPosition": Double(card.containerLayer.zPosition),
+                "bounds": dictionary(from: card.containerLayer.bounds),
                 "frame": dictionary(from: card.containerLayer.frame),
                 "visibleFrame": dictionary(from: visibleFrame),
                 "titleTruncationMode": "middle"
@@ -3513,16 +7542,41 @@
     private func waterfallCardVisualStates(for card: WaterfallCardLayers) -> [String] {
         var states: [String] = []
         let isSelected = card.item.window.id == effectiveSelection?.windowID
-        if shouldShowSelectedVisual(isSelected) {
+        let isHovered = card.item.window.id == hoveredWindowID
+        let isKeyboardFocused = card.item.window.id == keyboardFocusedWindowID
+        let isHorizontalAppDefaultFocused = isHorizontalAppDefaultCard(card)
+        let isAppLinked = isWaterfallCardAppLinked(card)
+        if shouldShowSelectedVisual(isSelected: isSelected, isHovered: isHovered)
+            || isKeyboardFocused
+            || isHorizontalAppDefaultFocused {
             states.append("selected")
         } else if isSelected {
             states.append("selectedVisualSuppressed")
         }
-        if card.item.window.id == hoveredWindowID {
+        if isKeyboardFocused {
+            states.append("keyboardFocused")
+        }
+        if isHorizontalAppDefaultFocused {
+            states.append("appDefault")
+        }
+        if isHovered {
             states.append("hover")
         }
-        if card.item.primarySpaceID == activeSpaceFocusID {
+        if isAppLinked {
+            states.append("appLinked")
+        }
+        if isWaterfallCardSpaceFocused(card) {
             states.append("spaceFocused")
+        }
+        switch windowShortcutFilterState(for: card) {
+        case .matched:
+            states.append("shortcutMatched")
+        case .dimmed:
+            states.append("shortcutDimmed")
+        case .target:
+            states.append("shortcutTarget")
+        case .none:
+            break
         }
         if card.item.window.isMinimized {
             states.append("minimized")
@@ -3537,32 +7591,111 @@
         window?.backingScaleFactor ?? NSScreen.main?.backingScaleFactor ?? 2
     }
 
+    private func spaceLaneDisplayGroupReports() -> [[String: Any]] {
+        spaceLaneDisplayGroups.map { group in
+            let visibleFrame = group.containerLayer.frame.offsetBy(dx: spaceLaneContentLayer.frame.minX, dy: 0)
+            return [
+                "displayUUID": group.display.displayUUID,
+                "displayIndex": group.display.displayIndex,
+                "displayLabel": group.display.displayLabel,
+                "physical": group.display.physical,
+                "spaceCount": group.segments.count,
+                "spaceIDs": group.segments.map(\.space.id),
+                "spaceLabels": group.segments.map(\.space.label),
+                "frame": dictionary(from: group.containerLayer.frame),
+                "visibleFrame": dictionary(from: visibleFrame),
+                "backgroundColor": colorDictionary(from: group.containerLayer.backgroundColor),
+                "borderColor": colorDictionary(from: group.containerLayer.borderColor),
+                "borderWidth": Double(group.containerLayer.borderWidth),
+                "shadowOpacity": Double(group.containerLayer.shadowOpacity),
+                "shadowRadius": Double(group.containerLayer.shadowRadius),
+                "groupGap": Double(SpaceLaneMetrics.groupGap),
+                "groupHorizontalPadding": Double(SpaceLaneMetrics.groupHorizontalPadding),
+                "groupVerticalPadding": Double(SpaceLaneMetrics.groupVerticalPadding),
+                "segmentGap": Double(SpaceLaneMetrics.segmentGap)
+            ] as [String: Any]
+        }
+    }
+
     private func spaceLaneSegmentReports() -> [[String: Any]] {
         currentViewModel?.displays.flatMap { display in
             display.spaces.compactMap { space in
                 guard let segment = spaceLaneSegments.first(where: { $0.space.id == space.id }) else {
                     return nil
                 }
-                let visibleFrame = segment.containerLayer.frame.offsetBy(dx: spaceLaneContentLayer.frame.minX, dy: 0)
+                let isAppAssociated = appHoverAssociatedSpaceIDs.contains(space.id)
+                let isWindowAssociated = space.id == windowHoverAssociatedSpaceID
+                let isLocked = space.id == currentViewModel?.lockedSpaceID
+                let isActive = space.id == activeSpaceFocusID || isLocked
+                let isAssociated = (isAppAssociated || isWindowAssociated) && !isActive
+                let usesLightActiveFill = resolvedTheme == .dark && space.windowCount > 0 && !isLocked && (isActive || isAssociated)
+                let group = spaceLaneDisplayGroup(containingSpaceID: space.id)
+                let visibleFrame = segment.containerLayer.frame.offsetBy(
+                    dx: (group?.containerLayer.frame.minX ?? 0) + spaceLaneContentLayer.frame.minX,
+                    dy: group?.containerLayer.frame.minY ?? 0
+                )
+                let fullscreenMarkerFrame = segment.fullscreenMarkerLayer?.frame
+                let fullscreenMarkerCenterRatio = fullscreenMarkerFrame.map {
+                    Double($0.midY / max(1, segment.containerLayer.bounds.height))
+                }
+                let splitAppNames = splitViewAppNames(for: space)
+                let splitAppLabelFrames = segment.splitAppLayers.map { dictionary(from: $0.frame) }
                 return [
                     "displayUUID": display.displayUUID,
                     "displayLabel": display.displayLabel,
+                    "spaceID": space.id,
                     "label": space.label,
                     "type": spaceTypeName(space.type),
                     "visualStates": visualStates(for: space),
+                    "usesLightActiveFill": usesLightActiveFill,
+                    "foregroundContrastStyle": usesLightActiveFill ? "darkOnLight" : "themeDefault",
                     "fullscreenMarkerVisible": segment.fullscreenMarkerLayer != nil,
-                    "fullscreenMarkerKind": segment.fullscreenMarkerLayer == nil ? "none" : "cornerBracket",
-                    "fullscreenMarkerFrame": segment.fullscreenMarkerLayer.map { dictionary(from: $0.frame) } ?? NSNull(),
+                    "fullscreenMarkerKind": fullscreenMarkerKind(
+                        markerLayer: segment.fullscreenMarkerLayer,
+                        splitAppNames: splitAppNames
+                    ),
+                    "fullscreenMarkerPathStyle": fullscreenMarkerPathStyle(
+                        markerLayer: segment.fullscreenMarkerLayer,
+                        splitAppNames: splitAppNames
+                    ),
+                    "fullscreenMarkerFrame": fullscreenMarkerFrame.map { dictionary(from: $0) } ?? NSNull(),
+                    "fullscreenMarkerCenterRatio": fullscreenMarkerCenterRatio ?? NSNull(),
+                    "splitViewAppNames": splitAppNames,
+                    "splitViewLabelFrames": splitAppLabelFrames,
+                    "splitViewLabelColors": segment.splitAppLayers.map {
+                        colorDictionary(from: $0.foregroundColor)
+                    },
                     "windowBlockCount": segment.windowBlocks.count,
+                    "windowBlockColors": segment.windowBlocks.map { colorDictionary(from: $0.backgroundColor) },
+                    "windowBlockFrames": segment.windowBlocks.map { dictionary(from: $0.frame) },
+                    "labelColor": colorDictionary(from: segment.labelLayer.foregroundColor),
+                    "countText": string(from: segment.countLayer.string),
+                    "countVisible": !segment.countLayer.isHidden && segment.countLayer.opacity > 0,
+                    "countColor": colorDictionary(from: segment.countLayer.foregroundColor),
+                    "appColor": colorDictionary(from: segment.appLayer.foregroundColor),
+                    "fullscreenMarkerStrokeColor": colorDictionary(
+                        from: (segment.fullscreenMarkerLayer as? CAShapeLayer)?.strokeColor
+                    ),
+                    "backgroundKind": spaceLaneFillKind(for: segment.containerLayer),
                     "backgroundColor": colorDictionary(from: segment.containerLayer.backgroundColor),
+                    "gradientColors": gradientColorDictionaries(from: segment.containerLayer),
+                    "borderColor": colorDictionary(from: segment.containerLayer.borderColor),
+                    "borderWidth": Double(segment.containerLayer.borderWidth),
+                    "shadowColor": colorDictionary(from: segment.containerLayer.shadowColor),
                     "shadowOpacity": Double(segment.containerLayer.shadowOpacity),
                     "shadowRadius": Double(segment.containerLayer.shadowRadius),
+                    "shadowOffset": [
+                        "width": Double(segment.containerLayer.shadowOffset.width),
+                        "height": Double(segment.containerLayer.shadowOffset.height)
+                    ],
                     "appFrame": dictionary(from: segment.appLayer.frame),
                     "frame": dictionary(from: segment.containerLayer.frame),
                     "visibleFrame": dictionary(from: visibleFrame),
                     "isCurrent": space.isCurrent,
-                    "isHovered": space.id == hoveredSpaceID,
+                    "isHovered": space.id == activeSpaceFocusID,
                     "isFocused": space.id == activeSpaceFocusID,
+                    "isAppAssociated": isAppAssociated,
+                    "isWindowAssociated": isWindowAssociated,
                     "windowCount": space.windowCount,
                     "appCount": space.appCount,
                     "appNames": space.appNames
@@ -3571,19 +7704,47 @@
         } ?? []
     }
 
+    private func spaceLaneDisplayGroup(containingSpaceID spaceID: UInt64) -> SpaceLaneDisplayGroupLayers? {
+        spaceLaneDisplayGroups.first { group in
+            group.segments.contains { $0.space.id == spaceID }
+        }
+    }
+
+    private func fullscreenMarkerKind(markerLayer: CALayer?, splitAppNames: [String]) -> String {
+        guard markerLayer != nil else { return "none" }
+        return splitAppNames.count >= 2 ? "splitViewPair" : "cornerBracket"
+    }
+
+    private func fullscreenMarkerPathStyle(markerLayer: CALayer?, splitAppNames: [String]) -> String {
+        guard markerLayer != nil else { return "none" }
+        return splitAppNames.count >= 2 ? "centerDividerOnly" : "cornerBracket"
+    }
+
     private func visualStates(for space: QuickSwitchSpaceViewModel) -> [String] {
         var states: [String] = []
         if space.isCurrent {
             states.append("current")
         }
-        if space.id == hoveredSpaceID {
+        if appHoverAssociatedSpaceIDs.contains(space.id) {
+            states.append("appAssociated")
+        }
+        if space.id == windowHoverAssociatedSpaceID {
+            states.append("windowAssociated")
+        }
+        if space.id == activeSpaceFocusID {
             states.append("hover")
         }
         if space.id == activeSpaceFocusID {
             states.append("focused")
         }
+        if space.id == currentViewModel?.lockedSpaceID {
+            states.append("locked")
+        }
         if space.type == .fullscreen {
             states.append("fullscreen")
+        }
+        if splitViewAppNames(for: space).count >= 2 {
+            states.append("splitView")
         }
         return states
     }
@@ -3610,6 +7771,16 @@
         ]
     }
 
+    private func string(from textLayerValue: Any?) -> String {
+        if let string = textLayerValue as? String {
+            return string
+        }
+        if let attributedString = textLayerValue as? NSAttributedString {
+            return attributedString.string
+        }
+        return ""
+    }
+
     private func colorDictionary(from color: CGColor?) -> [String: Double] {
         guard let color,
               let nsColor = NSColor(cgColor: color)?.usingColorSpace(.deviceRGB)
@@ -3629,4 +7800,37 @@
             "alpha": Double(nsColor.alphaComponent)
         ]
     }
+
+    private func gradientColorDictionaries(from layer: CALayer) -> [[String: Double]] {
+        guard let gradientLayer = layer as? CAGradientLayer else { return [] }
+        return (gradientLayer.colors ?? []).map { color in
+            let cgColor = color as! CGColor
+            return colorDictionary(from: cgColor)
+        }
+    }
+
+    private var darkBackdropLayerCount: Int {
+        darkBackdropAmbientLayers.count + 1
+    }
+
+    private var darkBackdropLayersVisible: Bool {
+        resolvedTheme == .dark
+            && darkBackdropAmbientLayers.allSatisfy { !$0.isHidden }
+            && !darkVignetteLayer.isHidden
+    }
+
+    private func backgroundGradientColorReports() -> [[String: Double]] {
+        gradientColorDictionaries(from: backgroundLayer)
+    }
+
+    private func spaceLaneFillKind(for layer: CALayer) -> String {
+        if !gradientColorDictionaries(from: layer).isEmpty {
+            return "gradient"
+        }
+        let background = colorDictionary(from: layer.backgroundColor)
+        if background["alpha", default: 0] <= 0.01 {
+            return "clear"
+        }
+        return "solid"
+    }
 }

--
Gitblit v1.9.3