---

name: custom-theme description: Author a Wisp custom theme CSS file that uses documented tokens and import constraints. Use when the user wants a custom look, hide the paragraph lead bar, restyle chat Markdown, override colors, or import a stylesheet under Settings → Appearance.

Custom Wisp theme CSS

Wisp injects one user stylesheet after the built-in theme. Prefer CSS variables on :root. Do not invent Settings toggles for one-off look changes.

Workflow

1. Ask what should change (lead bar, table size, accent, chat density, fonts).
2. Write a .css file in the project, usually theme.css.
3. Apply it:
   • Desktop: configure with action=set and values.custom_css set to the full stylesheet text. Empty string clears it.
   • Or tell the user to import the file under Settings → Appearance.
4. Confirm the change is visible. If a rule did nothing, the selector is wrong; do not add !important unless a built-in rule requires it.

Constraints

The host sanitizes CSS before inject. These are stripped:

• @import and @namespace
• every url(...)
• javascript:, expression(, behavior:, -moz-binding
• </style and <script
• NULs; payload longer than 64 KB is truncated

Do not rely on remote fonts, images, or other stylesheets. Name an installed font with configure ui_font_family / code_font_family instead.

Scope light/dark overrides with :root[data-theme="light"] and :root[data-theme="dark"]. System theme follows the OS, so also cover :root[data-theme="system"] when the user cares about both.

Tokens

Override these on :root. Leave unused tokens alone.

| Token | Default role | | --- | --- | | --bg-app, --bg-elev, --bg-sunken, --bg-input, --bg-panel | Surfaces | | --text, --text-muted, --text-faint | Ink | | --border, --border-strong | Hairlines | | --clay, --clay-strong, --clay-soft, --on-clay | Accent (teal) | | --ui-font-size, --code-font-size | Set by Appearance sliders; do not hard-code px on chat body | | --md-table-font-size | Markdown tables; default calc(var(--ui-font-size, 14px) - 1px) | | --md-lead-bar-width, --md-lead-bar-pad | Bold-at-start emphasis bar; 3px / 0.55em | | --font-user-ui, --font-user-mono | Optional family names; empty restores the stack | | --radius, --radius-sm, --radius-xs | Corners |

Palette attributes (data-light-palette, data-dark-palette) already map onto the semantic tokens. Prefer --clay / --bg-app over palette internals (--lp-*, --dp-*) unless the user asked to restyle one palette only.

Common requests

Hide the lead bar (the vertical mark before a paragraph that starts with bold):

:root {
  --md-lead-bar-width: 0;
  --md-lead-bar-pad: 0;
}

Keep tables aligned with UI size, or pin a size:

:root { --md-table-font-size: calc(var(--ui-font-size, 14px) - 1px); }

:root { --md-table-font-size: 14px; }

Quiet chat chrome:

.msg.assistant .role { display: none; }
.msg.assistant .body.md { letter-spacing: 0; }

Do not restyle window controls, settings forms, or tool-approval cards unless the user asked. Keep contrast readable on both themes.

Apply via configure

{
  "action": "set",
  "values": {
    "custom_css": ":root { --md-lead-bar-width: 0; --md-lead-bar-pad: 0; }\n"
  }
}

After writing theme.css, read it and pass the exact file contents. Do not summarize or wrap the CSS in Markdown fences inside custom_css.