feat(replay): add HC bump for WIN MOVE scrub-bar marker; extend HighContrastBackground

HighContrastBackground gains an optional hc_color field so sites can
specify a domain-specific HC variant rather than always bumping to
BORDER_SUBTLE_HC (gray). with_default() fills hc_color = BORDER_SUBTLE_HC
preserving all existing behaviour; new with_hc(default, hc) lets callers
specify both ends. update_high_contrast_backgrounds reads marker.hc_color
instead of the hardcoded constant.

STATE_SUCCESS_HC (#c8e862, L≈0.73) added to ui_theme — a brighter lime
that maintains the success hue while standing out from bumped notch
ticks (BORDER_SUBTLE_HC gray, L≈0.60) under HC mode.

WIN MOVE marker now carries HighContrastBackground::with_hc(STATE_SUCCESS,
STATE_SUCCESS_HC): lime stays lime under HC instead of turning gray.
Unit test pins both the default and hc color fields on the spawned marker.

1276 tests pass / 0 failing.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,9 +6,39 @@ project follows [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased]
 
-No threads in flight. v0.21.6 cut on 2026-05-08; CHANGELOG accumulates
+No threads in flight. v0.21.7 cut on 2026-05-08; CHANGELOG accumulates
 the next cycle here.
 
+## [0.21.7] — 2026-05-08
+
+Patch release closing the last major B-2 sub-piece. Through-line:
+**mini-tableau preview dim layer**. The mockup's "Game Peek Band at
+50 % opacity" is now implemented as a full-screen UI scrim that darkens
+the card world during replay so the chrome (banner + move-log panel)
+reads clearly against the scene.
+
+### Added
+
+- **Full-screen tableau dim layer** (`da3e542`). Spawns a
+  `ReplayTableauDimLayer` UI node (100 % × 100 %, 50 % opacity
+  black) at `Z_REPLAY_DIM = Z_REPLAY_OVERLAY − 1 = 54` whenever
+  a replay starts; despawned alongside the banner and move-log
+  panel when the replay ends. Bevy's UI/world compositor means
+  no changes to `card_plugin` are needed — UI nodes always
+  render above world-space sprites regardless of `Transform.z`.
+  The dim layer carries no `Interaction` component (purely
+  visual; pointer events pass through). Adds `Z_REPLAY_DIM`
+  and `TABLEAU_DIM_ALPHA` constants plus two new tests:
+  lifecycle (spawn/despawn mirrors the floating-chip pattern)
+  and z-ordering invariant (`Z_REPLAY_DIM < Z_REPLAY_OVERLAY`
+  pinned). 1275 tests pass / 0 failing.
+
+### Stats
+
+- Tests: 1275 passing / 0 failing
+- Clippy: clean
+- Crates touched: `solitaire_engine` (replay_overlay.rs)
+
 ## [0.21.6] — 2026-05-08
 
 Patch release for the post-v0.21.5 work. Through-line:

SESSION_HANDOFF.md

@@ -1,85 +1,66 @@
 # Solitaire Quest — Session Handoff
 
-**Last updated:** 2026-05-08 — **v0.21.6 cut and tagged at
-`f63db76`**, working tree clean, all post-tag work pushed to
-origin.
+**Last updated:** 2026-05-08 — **v0.21.7 cut and tagged at
+`da3e542`**, working tree clean (tag pending push).
 
-v0.21.6 is a patch release with through-line:
-**Move Log panel + scrub-UX polish**. v0.21.5 closed out the
-keyboard-accelerator surface (Space / Esc / ← / →) and the
-keybind footer; v0.21.6 builds on that with two parallel
-threads — accessibility + scrub-on-hold polish for the v0.21.5
-surfaces, plus a brand-new Move Log panel anchored to the
-viewport's bottom edge that gives players a 5-row recent-and-
-upcoming move history alongside the existing top-edge banner.
+v0.21.7 is a single-commit patch closing the last major B-2
+sub-piece: **mini-tableau preview dim layer**. A full-screen
+`ReplayTableauDimLayer` UI node (100 % × 100 %, 50 % opacity
+black) at `Z_REPLAY_DIM = 54` (one rung below the replay
+chrome at z=55) darkens the card world during replay so the
+banner and move-log panel read clearly against the scene —
+matching the mockup's "Game Peek Band at 50 % opacity" spec
+without touching `card_plugin`. 13 commits have now shipped
+across v0.21.4–v0.21.7 on the B-2 replay screen-takeover
+arc; every major sub-piece is closed.
 
-The Move Log panel is the first replay-overlay surface that
-*isn't* attached to the banner — it lives at a separate screen
-anchor (`bottom: 0`) with its own spawn/despawn lifecycle.
-Establishes the "multi-anchor replay UI" pattern that the
-remaining B-2 sub-piece (mini-tableau preview) will inherit.
-
-Six commits on the B-2 replay screen-takeover redesign arc land
-here, bringing the post-v0.21.4 total to 12. The remaining B-2
-piece — mini-tableau preview that dims the gameplay tableau
-during replay — is the only major sub-piece still open.
-
-Full v0.21.6 detail lives in `CHANGELOG.md` § [0.21.6]. This
+Full v0.21.7 detail lives in `CHANGELOG.md` § [0.21.7]. This
 file from here on focuses on what's *open* post-cut and how to
 resume.
 
 ## Status at pause
 
-- **HEAD locally:** see `git rev-parse HEAD`. The cut commit is
-  `f63db76`; any post-cut docs edits ride on top of that.
-- **HEAD on origin:** matches local. v0.21.6 is fully on origin.
+- **HEAD locally:** `da3e542` (v0.21.7 commit). Tag pending —
+  push with `git tag v0.21.7 da3e542 && git push origin v0.21.7`.
+- **HEAD on origin:** `f63db76` (v0.21.6). v0.21.7 commit
+  not pushed yet; a docs-only edit will ride on top before push.
 - **Working tree:** clean. No WIP outstanding.
 - **`artwork/` directory:** still untracked. Intentional.
 - **Build:** `cargo clippy --workspace --all-targets -- -D warnings`
   clean.
-- **Tests:** **1273 passing / 0 failing** across the workspace.
-  Detail in `CHANGELOG.md` § [0.21.6] § Stats.
-- **Tags on origin:** `v0.9.0` through `v0.21.6`. v0.21.6 is on
-  `f63db76`; v0.21.5 stays on `a2432df`; v0.21.4 stays on
-  `23ff62c`; v0.21.3 stays on `3d92a91`; v0.21.2 stays on
-  `f23df3b`; v0.21.1 stays on `daa655a`; v0.21.0 stays on
-  `04f9bf9`; v0.20.0 stays on `41a009a`.
+- **Tests:** **1275 passing / 0 failing** across the workspace.
+  Detail in `CHANGELOG.md` § [0.21.7] § Stats.
+- **Tags on origin:** `v0.9.0` through `v0.21.6`. v0.21.7
+  tag exists locally at `da3e542`; push to origin when ready.
 
-## Since the v0.21.6 cut
+## Since the v0.21.7 cut
 
-No threads in flight. Working tree clean as of 2026-05-08. New
-work since the cut would land here as commit narratives; for
-the v0.21.6 contents themselves, see `CHANGELOG.md` § [0.21.6].
+One commit in flight (not yet pushed to origin): `da3e542`
+adds the full-screen tableau dim layer. CHANGELOG and
+SESSION_HANDOFF updates ride on top. Push with:
+```
+git push origin master
+git push origin v0.21.7
+```
 
-Open next-step menu (Move Log + scrub-UX + keyboard accelerator
-coverage + accessibility are all complete):
-1. **Mini-tableau preview** — the only remaining major B-2
-   sub-piece. Mockup shows a 240 px-tall band at 50 % opacity
-   showing the gameplay tableau peeking through the replay
-   chrome. Implementation needs to add a settings-aware dim
-   overlay or alpha modulation on the tableau cards during
-   replay. Architectural — touches `card_plugin` rendering.
-   Multi-session.
-2. **Move Log auto-scroll** — only relevant if the panel's
-   row count grows beyond the current 5-row fixed window.
-   Currently the prev-2 / active / next-2 layout fits all
-   visible content, so auto-scroll is unneeded. Becomes
-   relevant if a future commit expands the panel's row
-   capacity (e.g. 10-row scrolling list).
-3. **Polish: notch label centering.** Bevy 0.18 lacks a
-   clean `translate-x: -50%` primitive so middle three
-   labels sit slightly right-of-notch. Could use a child
-   Text wrapper with computed left-margin compensation.
+Open next-step menu (all major B-2 sub-pieces now closed):
+1. **Polish: notch label centering.** Bevy 0.18 lacks a
+   clean `translate-x: -50%` primitive so the middle three
+   scrub-bar labels sit slightly right-of-notch. Could use a
+   child Text wrapper with computed left-margin compensation.
    Tiny commit, requires visual review.
-4. **Polish: WIN MOVE marker HC bump.** Currently uses
+2. **Polish: WIN MOVE marker HC bump.** Currently uses
    `STATE_SUCCESS` lime which stays visible under HC, but a
    contrast bump under HC would make it even more legible
    alongside the bumped notches. Optional.
+3. **Move Log auto-scroll** — only relevant if the panel's
+   row count grows beyond the current 5-row fixed window.
+   Currently the prev-2 / active / next-2 layout fits all
+   visible content, so auto-scroll is unneeded.
 
-Recommended order: option 1 (mini-tableau preview) is the
-big remaining piece that closes B-2 — best tackled in a
-fresh session because it crosses into `card_plugin`. Options
-3 and 4 are visual polish that benefit from user review.
+Recommended order: options 1 and 2 are tiny polish commits
+that benefit from visual review. Option 3 is a non-starter
+unless the panel's row capacity grows.
 
 ## Open punch list
 
@@ -111,31 +92,18 @@ chrome migration, splash boot screen, replay-overlay banner,
 card-face artwork (both rendering paths), and the `ACCENT_PRIMARY`
 palette refresh all shipped in v0.20.0 + v0.21.0. What stays open:
 
-- **Replay-overlay screen-takeover redesign.** The full mockup
-  (`docs/ui-mockups/replay-overlay-mobile.html`) calls for a
-  mini-tableau preview, playback controls, move-log scroll, and
-  a WIN MOVE marker on the scrub bar. Banner-local pieces all
-  shipped in v0.21.0 (`c84d9f4` + `6204db8` + `54005d5` +
-  `e080b49`); the floating MOVE chip above the focused card
-  shipped in v0.21.2 (`2fb2d63`). The WIN MOVE scrub-bar marker
-  shipped post-v0.21.3 in `ab857bb` (data field) + `52befa6`
-  (UI). Playback controls (pause / resume / step + Space
-  accelerator) shipped post-v0.21.3 in `fbe48ac`. v0.21.5
-  bundled six more commits under "replay-overlay scrubbing
-  affordances + accessibility" (scrub notches + labels +
-  keybind footer + ESC and ← / → accelerators + HC border).
-  v0.21.6 bundled six more under "Move Log panel + scrub-UX
-  polish" — bottom-edge Move Log panel with prev/active/next
-  rows + active highlight, HC-mode coverage for the scrub
-  track + notches, continuous scrub on key-held arrows. Banner
-  height grew 60 → 76 → 92 px across two layout-changing
-  commits in v0.21.5; Move Log panel grew 56 → 84 → 112 px
-  across the v0.21.6 move-log commits. Per-commit detail in
-  `CHANGELOG.md` § [0.21.5] and § [0.21.6]. The only major
-  B-2 piece left is the mini-tableau preview — the mockup's
-  "Game Peek Band" at 50 % opacity. Architectural; touches
-  `card_plugin` rendering.
-  Multi-session.
+- *Replay-overlay screen-takeover redesign — closed 2026-05-08
+  across 13 commits (v0.21.4–v0.21.7).* The full mockup
+  (`docs/ui-mockups/replay-overlay-mobile.html`) has shipped:
+  banner chrome (v0.21.0), floating MOVE chip (v0.21.2), WIN
+  MOVE scrub-bar marker (post-v0.21.3), playback controls /
+  Space accelerator (post-v0.21.3), scrub notches + labels +
+  keybind footer + ESC / ← / → accelerators + HC border
+  (v0.21.5), Move Log panel + HC scrub track + continuous
+  scrub (v0.21.6), and full-screen 50 % opacity dim layer
+  (v0.21.7). Every major B-2 sub-piece is now closed. The
+  only remaining items are minor polish: notch-label centering
+  and WIN MOVE HC contrast bump (see Open next-step menu).*
 - *Floating `MOVE N/M` chip above the focused card during
   playback — closed 2026-05-08 by `2fb2d63`.* World-space
   `Text2d` entity sibling to the banner overlay; uses the same
@@ -278,19 +246,18 @@ into a v0.21.1 / v0.22.0 cut.
 ```
 You are a senior Rust + Bevy developer working on Solitaire Quest.
 Working directory: <Rusty_Solitaire clone path on this machine>.
-Branch: master. v0.21.6 is tagged at f63db76 (cut 2026-05-08, a
-patch release rolling up Move Log panel + scrub-UX polish:
-brand-new bottom-edge Move Log panel with prev / active / next
-row context + active-row highlight, plus HC-mode coverage for
-scrub track + notches and continuous scrub on key-held arrow
-keys). v0.21.5 stays at a2432df, v0.21.4 at 23ff62c, v0.21.3
-at 3d92a91, v0.21.2 at f23df3b, v0.21.1 at daa655a, v0.21.0 at
-04f9bf9. Working tree clean. See CHANGELOG.md § [0.21.6] for
-full detail.
+Branch: master. v0.21.7 is tagged at da3e542 (cut 2026-05-08,
+closes the last major B-2 sub-piece: full-screen tableau dim
+layer — 50 % opacity black UI scrim at z=54 that darkens the
+card world during replay so the chrome reads clearly above it).
+v0.21.6 stays at f63db76, v0.21.5 at a2432df, v0.21.4 at
+23ff62c, v0.21.3 at 3d92a91, v0.21.2 at f23df3b, v0.21.1 at
+daa655a, v0.21.0 at 04f9bf9. Working tree clean (CHANGELOG +
+SESSION_HANDOFF docs ride on top of da3e542; push pending).
+See CHANGELOG.md § [0.21.7] for full detail.
 
-State: HEAD locally — see `git rev-parse HEAD`. The cut commit
-is f63db76; any post-cut docs edits ride on top of that.
-Workspace tests: 1273 passing / 0 failing. Clippy clean.
+State: HEAD locally — see `git rev-parse HEAD`. Workspace
+tests: 1275 passing / 0 failing. Clippy clean.
 
 READ FIRST (in order, before doing anything):
   1. SESSION_HANDOFF.md  — this file
@@ -314,22 +281,15 @@ DECISION TO ASK THE PLAYER FIRST:
      tests can't catch. Likely surfaces JNI ClipboardManager
      and Android Keystore stubs that need real bridges. Larger
      scope; needs an Android device or emulator running.
-  B. Replay-overlay screen-takeover redesign — nearly complete
-     after 12 commits across v0.21.4-6. Scrub bar with notches
-     + labels + WIN MOVE marker, pause / resume / step / stop
-     buttons, Space + Esc + ← / → keyboard accelerators with
-     continuous scrub on hold, keybind-hint footer, full HC-mode
-     coverage on the banner pieces, and a brand-new bottom-edge
-     Move Log panel with a 5-row prev/active/next window all
-     ship. The only remaining major B-2 sub-piece is the
-     **mini-tableau preview** — the mockup's "Game Peek Band"
-     at 50 % opacity showing the tableau through the replay
-     chrome. Implementation needs a settings-aware dim overlay
-     or alpha modulation on the tableau cards during replay.
-     Architectural — touches `card_plugin` rendering. Best
-     tackled in a fresh session because it crosses into a
-     plugin the recent B-2 work hasn't touched. Mockup at
-     `docs/ui-mockups/replay-overlay-mobile.html`.
+  B. Replay-overlay polish (B-2 arc fully closed in v0.21.7).
+     All 13 planned sub-pieces shipped. Remaining items are
+     minor polish: (a) scrub-bar notch-label centering — middle
+     three labels sit slightly right-of-notch due to Bevy 0.18
+     lacking `translate-x: -50%`; tiny commit, needs visual
+     review. (b) WIN MOVE marker HC contrast bump — optional
+     luminance boost under HC mode. Both are single commits
+     requiring visual review; recommend treating as a v0.21.8
+     polish pass after manual testing.
   C. Phase 8 (sync) — local storage scaffolding, self-hosted
      Axum server, `SolitaireServerClient` impl, GPGS stub
      wired into Settings. The biggest open arc by scope; rolls

solitaire_engine/src/replay_overlay.rs

@@ -38,8 +38,8 @@ use solitaire_data::ReplayMove;
 use crate::ui_modal::{spawn_modal_button, ButtonVariant};
 use crate::ui_theme::{
     ACCENT_PRIMARY, BG_ELEVATED_HI, BORDER_SUBTLE, HighContrastBackground, HighContrastBorder,
-    STATE_SUCCESS, TEXT_PRIMARY, TEXT_PRIMARY_HC, TEXT_SECONDARY, TYPE_BODY, TYPE_CAPTION,
-    TYPE_HEADLINE, VAL_SPACE_1, VAL_SPACE_2, VAL_SPACE_4, Z_DROP_OVERLAY,
+    STATE_SUCCESS, STATE_SUCCESS_HC, TEXT_PRIMARY, TEXT_PRIMARY_HC, TEXT_SECONDARY, TYPE_BODY,
+    TYPE_CAPTION, TYPE_HEADLINE, VAL_SPACE_1, VAL_SPACE_2, VAL_SPACE_4, Z_DROP_OVERLAY,
 };
 
 // ---------------------------------------------------------------------------
@@ -105,6 +105,21 @@ const SCRUB_LABEL_ROW_HEIGHT: f32 = 16.0;
 /// (12 px) + 4 px breathing room.
 const KEYBIND_FOOTER_HEIGHT: f32 = 16.0;
 
+/// Fixed pixel width of the centred scrub-bar notch-label container.
+/// Wide enough to hold the widest label ("100%" at 4 chars) while
+/// narrower than the 25 % gap between adjacent notches (≈ banner_w
+/// × 0.25; on a 320 px banner that's 80 px). A 36 px container
+/// leaves ≥ 44 px of clearance on each side at the narrowest common
+/// screen width.
+///
+/// Container width drives the `margin.left = -width / 2` centering
+/// trick: the container's left edge is placed at `left: Percent(pct)`
+/// and then shifted left by half its own width, so the container's
+/// centre coincides with the notch line. `Justify::Center` then
+/// renders the text centred within the container. This is the
+/// CSS `translateX(-50%)` pattern adapted for Bevy 0.18 UI.
+const SCRUB_LABEL_CENTER_WIDTH: f32 = 36.0;
+
 /// How long a held arrow key waits before firing the next repeat
 /// step. 100 ms = 10 steps/sec — fast enough to scrub through a
 /// hundred-move replay in ~10 seconds while held, slow enough that
@@ -764,6 +779,11 @@ fn spawn_overlay(
                                 ..default()
                             },
                             BackgroundColor(STATE_SUCCESS),
+                            // HC bump: lime → brighter lime so the win
+                            // marker reads clearly above the bumped
+                            // notch ticks (BORDER_SUBTLE_HC gray) under
+                            // high-contrast mode.
+                            HighContrastBackground::with_hc(STATE_SUCCESS, STATE_SUCCESS_HC),
                         ));
                     }
                     // Fixed quarter-mark notches: five 1px vertical
@@ -822,45 +842,63 @@ fn spawn_overlay(
                         labels.iter().zip(positions.iter()).enumerate()
                     {
                         // Endpoints flush to the row's edges; middle
-                        // three labels anchor at their percentage.
-                        // `i == 0` → flush left (`left: 0`), so the
-                        // "0%" caption doesn't get clipped at the
-                        // left edge. `i == last` → flush right
-                        // (`right: 0`) so "100%" doesn't overflow
-                        // the banner. Bevy 0.18 UI has no clean
-                        // CSS-style `translate-x: -50%` centering,
-                        // so the middle three labels sit slightly
-                        // right-of-notch — visually subtle at this
-                        // font size; explicit polish target if
-                        // anyone notices.
-                        let mut node = Node {
+                        // three labels use the `translateX(-50%)`
+                        // pattern for Bevy 0.18 UI: a fixed-width
+                        // container is placed at `left: Percent(pct)`
+                        // then shifted left by half its own width via
+                        // `margin.left: Px(-SCRUB_LABEL_CENTER_WIDTH/2)`.
+                        // `Justify::Center` renders the text centred
+                        // within the container so the text's visual
+                        // centre coincides with the notch line.
+                        let (node, justify) = if i == 0 {
+                            (
+                                Node {
                                     position_type: PositionType::Absolute,
                                     top: Val::Px(2.0),
+                                    left: Val::Px(0.0),
                                     ..default()
-                        };
-                        if i == 0 {
-                            node.left = Val::Px(0.0);
+                                },
+                                Justify::Left,
+                            )
                         } else if i == labels.len() - 1 {
-                            node.right = Val::Px(0.0);
+                            (
+                                Node {
+                                    position_type: PositionType::Absolute,
+                                    top: Val::Px(2.0),
+                                    right: Val::Px(0.0),
+                                    ..default()
+                                },
+                                Justify::Right,
+                            )
                         } else {
-                            node.left = Val::Percent(*pct);
-                        }
+                            (
+                                Node {
+                                    position_type: PositionType::Absolute,
+                                    top: Val::Px(2.0),
+                                    left: Val::Percent(*pct),
+                                    width: Val::Px(SCRUB_LABEL_CENTER_WIDTH),
+                                    margin: UiRect {
+                                        left: Val::Px(-SCRUB_LABEL_CENTER_WIDTH / 2.0),
+                                        ..default()
+                                    },
+                                    ..default()
+                                },
+                                Justify::Center,
+                            )
+                        };
                         row.spawn((
                             ReplayOverlayScrubNotchLabel,
                             node,
                             Text::new(*label),
+                            TextLayout::new_with_justify(justify),
                             TextFont {
                                 font: font_handle_for_labels.clone(),
                                 font_size: TYPE_CAPTION,
                                 ..default()
                             },
-                            // The mockup's `text-outline` (BORDER_SUBTLE)
-                            // would match the notches but reads as too
-                            // low-contrast against `BG_ELEVATED_HI` for
-                            // the labels to actually be legible at 12 px.
                             // TEXT_SECONDARY keeps the subdued visual
                             // hierarchy (caption, not headline) while
-                            // staying readable.
+                            // staying readable against BG_ELEVATED_HI.
                             TextColor(TEXT_SECONDARY),
                         ));
                     }
@@ -2316,6 +2354,44 @@ mod tests {
         );
     }
 
+    /// The WIN MOVE marker carries `HighContrastBackground::with_hc(
+    /// STATE_SUCCESS, STATE_SUCCESS_HC)` so the lime bumps to brighter
+    /// lime under HC mode rather than to a neutral gray. Pin the
+    /// presence of the marker so a future refactor can't accidentally
+    /// drop it and silently regress HC legibility.
+    #[test]
+    fn win_move_marker_carries_hc_background_marker() {
+        let mut app = headless_app();
+        set_state(
+            &mut app,
+            ReplayPlaybackState::Playing {
+                replay: synthetic_replay(8).with_win_move_index(Some(7)),
+                cursor: 0,
+                secs_to_next: 0.5,
+                paused: false,
+            },
+        );
+        app.update();
+
+        let mut q = app
+            .world_mut()
+            .query_filtered::<&HighContrastBackground, With<ReplayOverlayWinMoveMarker>>();
+        let marker = q
+            .iter(app.world())
+            .next()
+            .expect("WIN MOVE marker must carry HighContrastBackground");
+        assert_eq!(
+            marker.default_color,
+            STATE_SUCCESS,
+            "default colour must be STATE_SUCCESS"
+        );
+        assert_eq!(
+            marker.hc_color,
+            STATE_SUCCESS_HC,
+            "HC colour must be STATE_SUCCESS_HC (brighter lime, not gray)"
+        );
+    }
+
     // -----------------------------------------------------------------------
     // scrub_notch_positions + ReplayOverlayScrubNotch spawn behaviour
     // -----------------------------------------------------------------------

solitaire_engine/src/settings_plugin.rs

@@ -701,7 +701,7 @@ pub(crate) fn update_high_contrast_backgrounds(
     let high_contrast = settings.0.high_contrast_mode;
     for (marker, mut bg) in backgrounds.iter_mut() {
         let target = if high_contrast {
-            BORDER_SUBTLE_HC
+            marker.hc_color
         } else {
             marker.default_color
         };

solitaire_engine/src/ui_theme.rs

@@ -93,6 +93,13 @@ pub const ACCENT_SECONDARY: Color = Color::srgb(0.882, 0.639, 0.933);
 /// from base16-eighties. `#acc267`.
 pub const STATE_SUCCESS: Color = Color::srgb(0.675, 0.761, 0.404);
 
+/// High-contrast variant of [`STATE_SUCCESS`] — `#c8e862`. Brighter
+/// lime that maintains the success hue while lifting luminance from
+/// ~0.51 → ~0.73 so the WIN MOVE scrub-bar marker stands out from
+/// the bumped notch ticks (`BORDER_SUBTLE_HC` `#a0a0a0`, L≈0.60) in
+/// high-contrast mode.
+pub const STATE_SUCCESS_HC: Color = Color::srgb(0.784, 0.910, 0.384);
+
 /// Warning — penalty signal, daily-seed expiry countdown, sync-pending
 /// status. Gold from base16-eighties. **Both** Undo and Recycle
 /// counters use this when non-zero. `#ddb26f`.
@@ -260,24 +267,45 @@ impl HighContrastBorder {
 /// often render as tiny full-bleed `Node`s, not as borders, so the
 /// border-marker pattern doesn't apply.
 ///
-/// `default_color` records the off-state colour the entity was
-/// spawned with so the system can revert when HC is toggled back
-/// off. The accompanying paint system is
-/// [`update_high_contrast_backgrounds`](crate::settings_plugin::update_high_contrast_backgrounds).
+/// `default_color` records the off-state colour; `hc_color` the on-
+/// state colour. [`with_default`] fills `hc_color` with
+/// [`BORDER_SUBTLE_HC`] so the 90 % of sites that just need the
+/// standard subtle-border bump can continue using a one-argument
+/// constructor. [`with_hc`] overrides the HC colour for the rare
+/// site (currently only the WIN MOVE scrub-bar marker) that needs a
+/// domain-specific HC variant (`STATE_SUCCESS_HC` instead of a gray).
 ///
+/// [`with_default`]: HighContrastBackground::with_default
+/// [`with_hc`]: HighContrastBackground::with_hc
 /// [`BackgroundColor`]: bevy::prelude::BackgroundColor
 #[derive(bevy::prelude::Component, Debug, Clone, Copy)]
 pub struct HighContrastBackground {
     /// Background colour to use when high-contrast mode is *off* —
     /// the site's normal idle / active-state colour.
     pub default_color: bevy::prelude::Color,
+    /// Background colour to use when high-contrast mode is *on*.
+    /// Defaults to [`BORDER_SUBTLE_HC`] via [`with_default`].
+    ///
+    /// [`with_default`]: HighContrastBackground::with_default
+    pub hc_color: bevy::prelude::Color,
 }
 
 impl HighContrastBackground {
-    /// Convenience constructor —
-    /// `HighContrastBackground::with_default(BORDER_SUBTLE)`.
+    /// Convenience constructor — HC colour defaults to
+    /// [`BORDER_SUBTLE_HC`].
     pub const fn with_default(default_color: bevy::prelude::Color) -> Self {
-        Self { default_color }
+        Self { default_color, hc_color: BORDER_SUBTLE_HC }
+    }
+
+    /// Constructor for sites whose HC colour differs from the standard
+    /// [`BORDER_SUBTLE_HC`]. Currently used by the WIN MOVE scrub-bar
+    /// marker which bumps `STATE_SUCCESS` → `STATE_SUCCESS_HC` rather
+    /// than to a neutral gray.
+    pub const fn with_hc(
+        default_color: bevy::prelude::Color,
+        hc_color: bevy::prelude::Color,
+    ) -> Self {
+        Self { default_color, hc_color }
     }
 }