bb-theme-github-high-contrast

A custom theme for bb based on the GitHub high contrast palette, with color-coded sidebar thread indicators.

What it does

• Sets the bb palette (canvas, ink, primary, semantic colors) for light and dark mode.
• Uses the github-light-high-contrast and github-dark-high-contrast code themes for diffs and file previews.
• Gives every sidebar thread indicator its own color. Stock bb renders most of them in muted grey.
• Removes the opacity mask from animated indicators so they always render at full color.
• Enlarges the unread-success dot from 5px to 8px and thickens the working spinner stroke from 1.5 to 2.5.
• Colors thread panes by focus with 84EM brand colors (dark mode): focused pane on obsidian #090e1e, unfocused panes on black with slate-500 borders.
• Split pane title pill, prompt box border, and send button change color with pane focus: navy (#004c7e pill, #58a6ff border and button) when focused, orange (#b54600 pill and border, #e8935a button) when not.
• Fills the active right-panel tab with --primary and outlines inactive tabs with --border.
• Underlines the thread header in brand green #9ff400 while a run is active.
• Colors the thread header status glyph (bb 0.45.0+) in brand green #9ff400 for working states in dark mode (14.1:1 on the focused pane, 15.4:1 on black). Other header states and light mode use the indicator colors below.
• Sets --border-seam, --border-hairline, and --sidebar-border to --border, so pane seams and separators match the high contrast component borders.

Indicator colors

--primary and every indicator color measure at least 11:1 contrast against the canvas (#ffffff light, #000000 dark), computed with the WCAG 2.x relative luminance formula. Other palette tokens are not held to that floor.

State	Light	Dark
Thread failed, queued message failed	#7a0d18	#ffa4a2
Needs user input	#573400	#f0b72f
Message waiting to send	#642b00	#ffa95c
Thread working	#023787	#84c1ff
Workflow, background agent, background command	#4a218e	#d3acff
Plan mode, goal	#044343	#39d0d0
Unread thread succeeded	#034619	#2cd854
Unsubmitted draft	foreground	foreground

The colors live in the --ind-* custom properties in theme.css.

Install

1. Run bb theme dir to print the custom theme directory.

2. Clone this repo into that directory as github-high-contrast:

   git clone git@github.com:84emllc/bb-theme-github-high-contrast.git "$(bb theme dir)/github-high-contrast"

3. Activate it:

   bb theme set github-high-contrast

After editing theme.css, run bb theme set github-high-contrast again to re-apply.

Known limitations

• The indicator rules select on bb's internal aria-label strings (for example Thread needs user input). A bb update that renames those labels will silently drop the colors until the selectors are updated.
• At 11:1 on a white canvas, the light mode indicator colors are all close to black, so hues are harder to tell apart than in dark mode. Icon shape still distinguishes the states.
• Contrast is measured against the plain canvas. A selected sidebar row carries a primary tint, so contrast there is lower.
• Animated indicators no longer shimmer, because the shine effect is an opacity mask. The working spinner still rotates.
• An idle draft icon can render without an aria-label, in which case it keeps the stock color.
• The pane, tab, prompt box, and working-state rules select on bb's internal data-split-pane-id, data-focused, data-pane-header-focus-tab, data-secondary-panel-tab-content, group/tab-pill, aria-pressed, data-promptbox, data-promptbox-send-menu, data-thread-header-status, and the Stop run button label. The unfocused title pill has no data hook and is matched structurally. bb 0.45.0 exposes every thread state in the thread window (https://github.com/84emllc/bb/issues/33), but the active-run underline still keys on the Stop run button because data-thread-status reports only the highest-priority state.
• The compact (narrow viewport) panel shelf uses different markup and keeps the stock tab styling.
• Pane focus colors apply to the outer pane wrapper only. Popovers and menus render outside the pane and keep the root palette. A single open thread is always focused.
• The brand green working line is 1.4:1 on a white canvas, so it is faint in light mode.