fix(sidebar): restyle session history as a quiet overlay scrollbar

The native always-on track and white chrome were competing with the parchment sidebar. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-08-19 18:36:36 +08:00
parent bffc74efc5
commit 99833eba56
3 changed files with 36 additions and 1 deletions
@@ -154,6 +154,7 @@ The base unit is 4px. Tokens are `--space-1: 4px`, `--space-2: 8px`, `--space-3:
 - **Mobile:** no icon rail; an off-canvas drawer uses `min(86vw, 320px)` and closes through its scrim or Escape.
 - **Collapsed content:** logo, new-chat action, one history expansion action, and account avatar. Individual sessions do not become indistinguishable repeated icons.
 - **Scroll ownership:** header and footer remain fixed; `SidebarContent` is the sole sidebar scroll owner.
+- **Scrollbar:** `SidebarContent` uses a quiet overlay scrollbar: transparent track, no `scrollbar-gutter`, and a 4px warm thumb mixed from `--color-ink`. The thumb stays transparent until hover or keyboard focus inside the history, then uses `color-mix(in srgb, var(--color-ink) 26%, transparent)`; thumb hover uses 40%. Increased contrast keeps the thumb visible; forced colors restore the system scrollbar.
 - **Motion:** Sidebar state changes are immediate on desktop, tablet, and mobile. The 44px trigger keeps one stable 18px sidebar glyph and never enters an intermediate scale or opacity state.
 - **Accessibility:** Command/Control+B shortcut outside editable controls, contextual trigger labels, 44px targets, focus return, collapsed-only tooltips, reduced-motion, reduced-transparency, and increased-contrast support.
 - **State:** session-local; reload uses breakpoint defaults rather than cookie or local-storage persistence.