cmux-next: an unfocused pane's tabs fade further, so the focused pane is plain to see

Packages/macOS/CmuxNext/Sources/CmuxNextDesign/ChromeEmphasis.swift

@@ -61,7 +61,8 @@ extension ThemeTokens {
             t.textSecondary = fade(textSecondary, s, floor: Self.subtleSecondaryFloor)
             t.textTertiary = fade(textTertiary, s, floor: Self.subtleTertiaryFloor)
             t.selectionFill = selectionFill.withAlpha(selectionFill.alpha * (1 - s))
-            t.hoverFill = hoverFill.withAlpha(hoverFill.alpha * (1 - s))
+            // Hover fades half as much: hovering a tab is how a person picks that pane next.
+            t.hoverFill = hoverFill.withAlpha(hoverFill.alpha * (1 - s * 0.5))
         case .tonal:
             t.textPrimary = textSecondary
             t.textSecondary = textTertiary

Packages/macOS/CmuxNext/Sources/CmuxNextDesign/FocusIndicatorTunables.swift

@@ -12,8 +12,8 @@ public nonisolated enum FocusIndicatorTunables {
         default: .fade, code: "FocusIndicatorTunables.inactiveTabStyle")
     public static let inactiveTabStrength = Tunable<CGFloat>.number(
         "focus.inactiveTabStrength", .focus, "Unfocused tabs strength",
-        help: "How much subtler an unfocused pane's tabs draw (0 is the same as the focused pane).",
-        default: 0.35, range: 0...1, step: 0.05, unit: .fraction, code: "FocusIndicatorTunables.inactiveTabStrength")
+        help: "How much subtler an unfocused pane's tabs draw (0 is the same as the focused pane). 0.6 since 2026-10-21 (was 0.35): with no ring by default, the tabs are the cue for which pane Cmd-W closes.",
+        default: 0.6, range: 0...1, step: 0.05, unit: .fraction, code: "FocusIndicatorTunables.inactiveTabStrength")
 
     public static var all: [TunableDescriptor] {
         [indicator.descriptor, inactiveTabStyle.descriptor, inactiveTabStrength.descriptor]

Packages/macOS/CmuxNext/Sources/CmuxNextLayout/Model/LayoutStyle.swift

@@ -69,7 +69,7 @@ public nonisolated struct LayoutStyle: Hashable, Sendable {
     /// subtler when it marks tabs (`ChromeEmphasis.forPane`).
     public var focusIndicator: FocusIndicator = .tabs
     public var inactiveTabStyle: InactiveTabStyle = .fade
-    public var inactiveTabStrength: CGFloat = 0.35
+    public var inactiveTabStrength: CGFloat = 0.6
     /// Fraction of a pane's extent that counts as an edge drop zone
     /// (DESIGN.md (c)2: a quarter, half of the half a split gives).
     public var dropEdgeFraction: CGFloat = 0.25

Packages/macOS/CmuxNext/Tests/CmuxNextDesignTests/FocusedPaneTabCueTests.swift

@@ -0,0 +1,50 @@
+import CmuxNextDesign
+import CmuxTheme
+import Testing
+
+/// Leo, 2026-10-21: a link opened in a split beside his chat, and Cmd-W closed the chat, because
+/// nothing showed which pane had focus. With the default `appearance.focusIndicator` (tabs, no
+/// ring) the only cue is the other panes' subtler tabs, so they must read clearly as "not this
+/// one": the selected tab's pill at no more than half its focused fill, while every tab label
+/// stays readable.
+@Suite struct FocusedPaneTabCueTests {
+    static let themes: [ThemeTokens] = [
+        ThemeTokens.derive(from: ThemeInput(background: ThemeRGB(hex: 0x1E1E1E), foreground: ThemeRGB(hex: 0xD4D4D4))),
+        ThemeTokens.derive(from: ThemeInput(background: ThemeRGB(hex: 0x101018), foreground: ThemeRGB(hex: 0xE8E8F0))),
+        ThemeTokens.derive(from: ThemeInput(background: ThemeRGB(hex: 0xFFFFFF), foreground: ThemeRGB(hex: 0x24292F))),
+        ThemeTokens.derive(from: ThemeInput(background: ThemeRGB(hex: 0xF5F5F0), foreground: ThemeRGB(hex: 0x333333))),
+    ]
+
+    /// The emphasis an unfocused pane's tabs get by default.
+    static var unfocused: ChromeEmphasis {
+        ChromeEmphasis.forPane(isFocused: false, paneCount: 2, indicator: .tabs,
+                               style: FocusIndicatorTunables.inactiveTabStyle.defaultValue,
+                               strength: FocusIndicatorTunables.inactiveTabStrength.defaultValue)
+    }
+
+    @Test func anUnfocusedPanesSelectedTabIsClearlyNotTheFocusedOne() {
+        for tokens in Self.themes {
+            let subtle = tokens.emphasized(Self.unfocused)
+            #expect(subtle.selectionFill.alpha <= tokens.selectionFill.alpha * 0.5 + 0.0001,
+                    "the unfocused pill is at most half the focused one (\(subtle.selectionFill.alpha) of \(tokens.selectionFill.alpha))")
+            let page = tokens.contentBackground.withAlpha(1)
+            #expect(subtle.textPrimary.contrast(with: page) < tokens.textPrimary.contrast(with: page) * 0.6,
+                    "the unfocused selected label is plainly fainter")
+        }
+    }
+
+    @Test func unfocusedTabLabelsStayReadable() {
+        for tokens in Self.themes {
+            let subtle = tokens.emphasized(Self.unfocused)
+            let page = tokens.contentBackground.withAlpha(1)
+            #expect(subtle.textPrimary.contrast(with: page) >= min(ThemeTokens.subtlePrimaryFloor, tokens.textPrimary.contrast(with: page)) - 0.05)
+            #expect(subtle.textSecondary.contrast(with: page) >= min(ThemeTokens.subtleSecondaryFloor, tokens.textSecondary.contrast(with: page)) - 0.05)
+        }
+    }
+
+    /// The focused pane and a lone pane keep full strength.
+    @Test func theFocusedPaneKeepsFullStrength() {
+        #expect(ChromeEmphasis.forPane(isFocused: true, paneCount: 2, indicator: .tabs, style: .fade, strength: 0.6) == .full)
+        #expect(ChromeEmphasis.forPane(isFocused: false, paneCount: 1, indicator: .tabs, style: .fade, strength: 0.6) == .full)
+    }
+}

plans/cmux-next/focus.md

@@ -658,7 +658,7 @@ the user."):
   settings; `focus.inactiveTabStyle` overrides the cmux.json key of the same name (`fade` default: text, icons
   and pills fade toward the background; `tonal`: every text tier steps down, the selected
   pill takes the hover fill; `quiet`: no pill, the selection is the text tier);
-  `focus.inactiveTabStrength` (0.35). Subtle text never drops below 3.5:1 (selected),
+  `focus.inactiveTabStrength` (0.6; 0.35 until 2026-10-21, when Leo could not tell which pane Cmd-W would close). Subtle text never drops below 3.5:1 (selected),
   2.5:1 and 2:1 against the page (`ThemeTokens.subtle*Floor`). Panels and hover cards
   opened from a subtle strip adopt `ThemeScope.fullStrength`, so they draw at full strength.
 - With `appearance.borders` none the unfocused panes' dim stands in for the ring only when

plans/cmux-next/spec-proposals/visuals/components/tabs.md

@@ -68,15 +68,15 @@ Pressed screenshots are UNVERIFIED: a synthetic mouse-down enters AppKit's track
 
 ## Unfocused pane tabs (focus.inactiveTabStyle)
 
-Applies when `appearance.focusIndicator` is `tabs` or `both`, the screen has more than one pane, and the pane is not focused (`CmuxNextDesign/ChromeEmphasis.swift:30-77 (ChromeEmphasis.forPane, ThemeTokens.emphasized)`). Style: cmux.json `focus.inactiveTabStyle`, `fade` (default), `tonal` or `quiet`; Settings > Appearance > Unfocused Pane Tabs; the Debug tunable of the same name overrides it. Strength 0.35 (Debug tunable `focus.inactiveTabStrength`). Contrast floors: primary 3.5, secondary 2.5, tertiary 2.0. Fade step: `fade` starts at the strength and steps the mix fraction down by 0.02 until the color holds min(floor, its own contrast) against the page; tonal and quiet fade the tertiary tier by strength / 2.
+Applies when `appearance.focusIndicator` is `tabs` or `both`, the screen has more than one pane, and the pane is not focused (`CmuxNextDesign/ChromeEmphasis.swift:30-77 (ChromeEmphasis.forPane, ThemeTokens.emphasized)`). Style: cmux.json `focus.inactiveTabStyle`, `fade` (default), `tonal` or `quiet`; Settings > Appearance > Unfocused Pane Tabs; the Debug tunable of the same name overrides it. Strength 0.6 (Debug tunable `focus.inactiveTabStrength`; 0.35 until 2026-10-21). Contrast floors: primary 3.5, secondary 2.5, tertiary 2.0. Fade step: `fade` starts at the strength and steps the mix fraction down by 0.02 until the color holds min(floor, its own contrast) against the page; tonal and quiet fade the tertiary tier by strength / 2.
 
 | style | textPrimary | textSecondary | selectionFill | hoverFill |
 |---|---|---|---|---|
-| fade (default) | mixed toward the page by 0.35, floor 3.5 | mixed, floor 2.5 | alpha × 0.65 | alpha × 0.65 |
-| tonal | ← textSecondary | ← textTertiary | hoverFill alpha × 0.825 | unchanged |
-| quiet | ← textSecondary | textTertiary faded by 0.175 | transparent | unchanged |
+| fade (default) | mixed toward the page by 0.6, floor 3.5 | mixed, floor 2.5 | alpha × 0.4 | alpha × 0.7 (half the strength) |
+| tonal | ← textSecondary | ← textTertiary | hoverFill alpha × 0.7 | unchanged |
+| quiet | ← textSecondary | textTertiary faded by 0.3 | transparent | unchanged |
 
-Resolved for Apple System dark: fade primary `#B0B0B0`, selection `#FFFFFF11`; tonal selection `#FFFFFF0D`; quiet selection none. All themes: `components["tabs.inactivePaneEmphasis"].resolved` in the JSON. Screenshot check (dark): selected tab in the unfocused pane is `#2D2D2D` (fade), `#292929` (tonal), `#1E1E1E` (quiet).
+Resolved at the earlier strength 0.35, Apple System dark: fade primary `#B0B0B0`, selection `#FFFFFF11`; tonal selection `#FFFFFF0D`; quiet selection none. All themes: `components["tabs.inactivePaneEmphasis"].resolved` in the JSON. Screenshot check (dark): selected tab in the unfocused pane is `#2D2D2D` (fade), `#292929` (tonal), `#1E1E1E` (quiet).
 
 ![Unfocused pane tabs: fade](../images/tabs/dark-inactive-pane-fade.png)
 ![Unfocused pane tabs: tonal](../images/tabs/dark-inactive-pane-tonal.png)

plans/cmux-next/spec-proposals/visuals/design-tokens.json

@@ -2581,8 +2581,8 @@
      "quiet"
     ],
     "default": "fade",
-    "strength": 0.35,
-    "cmuxJson": "focus.inactiveTabStyle (Settings > Appearance > Unfocused Pane Tabs); the Debug Settings tunable of the same name overrides it. focus.inactiveTabStrength (0.35) stays a Debug tunable."
+    "strength": 0.6,
+    "cmuxJson": "focus.inactiveTabStyle (Settings > Appearance > Unfocused Pane Tabs); the Debug Settings tunable of the same name overrides it. focus.inactiveTabStrength (0.6) stays a Debug tunable."
    },
    "source": "Packages/macOS/CmuxNext/Sources/CmuxNextSettings/PaneFocusSettings.swift (PaneFocusSettings.inactiveTabStylePath); Packages/macOS/CmuxNext/Sources/CmuxNextDesign/DesignSettings.swift (DesignSettings.inactiveTabStyle, effectiveInactiveTabStyle); Packages/macOS/CmuxNext/Sources/CmuxNextDesign/FocusIndicatorTunables.swift:9-16 (FocusIndicatorTunables.inactiveTabStyle)"
   },
@@ -3216,7 +3216,7 @@
     "Packages/macOS/CmuxNext/Sources/CmuxNextDesign/FocusIndicatorTunables.swift:9-16 (FocusIndicatorTunables.inactiveTabStyle)"
    ],
    "metrics": {
-    "strength": 0.35,
+    "strength": 0.6,
     "floors": {
      "primary": 3.5,
      "secondary": 2.5,

plans/cmux-next/spec-proposals/visuals/design-tokens.md

@@ -255,7 +255,7 @@ Reduce Motion: no movement springs and no loops; fades capped at 0.1 s; the atte
 | appearance.tabBarBackground | retired | ignored: every surface draws the one window background |
 | focusRing.contrast | subtle 0.20, standard 0.55, strong 0.85 | ring alpha |
 | focusRing.{enabled,style,color,width,cornerRadius,showWhenSinglePane} | true, ring, nil, 1, nil, false | |
-| focus.inactiveTabStyle (the Debug tunable of the same name overrides it) | fade, tonal, quiet; strength 0.35 (Debug tunable) | see tabs page (`CmuxNextSettings/PaneFocusSettings.swift (PaneFocusSettings.inactiveTabStylePath)`) |
+| focus.inactiveTabStyle (the Debug tunable of the same name overrides it) | fade, tonal, quiet; strength 0.6 (Debug tunable) | see tabs page (`CmuxNextSettings/PaneFocusSettings.swift (PaneFocusSettings.inactiveTabStylePath)`) |
 | sidebar.sectionLook (Debug tunable `sidebar.sections.look` overrides it) | quiet, card, tray, lines, linesIcons | see sidebar page |
 | sidebar.topBandMaxShare / bottomBandMaxShare / pinnedBandsScroll | 1/3, 0.25 (range 0.1-0.9), true | share of the sidebar height a pinned band takes before it scrolls inside; false: bands never scroll and the list shrinks (three rows minimum) |
 | notifications.attention.* | style blink, width 2, blinkCount 2, duration 3 s, persist true | pane attention ring. Blink: blinkCount blinks over 0.5 s each (1.0 s for 2), then holds. duration applies to the pulse style only |