Built-in colour themes (Aurora, Ember, Mint) with a palette picker under Settings > General

[PHSchr3ck3]

Problem

The default palette is a neutral blue-grey. Sessions in Harness are long, and a fair number of users end up wanting something warmer, softer or simply a different accent. Today that means overriding --dsw-* tokens by hand, per project, with no discoverable place in the UI and no way to switch quickly.

Proposal

Ship two or three first-class palettes and a picker:

• Aurora — cool blue/violet, close to the current default
• Ember — warm amber, easier on the eyes in the evening
• Mint — teal/green, calm and high legibility

Each palette provides light and dark values and follows the system appearance.

UI

One row under Settings > General: Theme palette, with the three options plus Default. The selection is stored per profile, applied immediately and survives restarts.

Implementation sketch

• Themes are pure token overrides; no harness files are patched.
• Host side: hook webserver/index-inject and add exactly one <style> block to the page head.
• Client side: register the row through settings.general.item.
• Suggested internals: a theme registry keyed by id, one CSS variable layer per palette, and a prefers-color-scheme media query for the light/dark split.
• Ideally hot-swappable: injections are currently collected once at boot, so a palette change needs an app restart today. A small theme service that swaps the style node would avoid that.

Acceptance criteria

• Palette switch without restart, or an explicit "restart required" hint.
• No flash of the default palette on load.
• Contrast checked for body text, muted text, borders and accent-on-surface.
• Works in the web GUI and in the desktop shell.

Reference implementation

A community bundle that implements exactly this is available at https://github.com/PHSchr3ck3/dsh-theme-vivid (MIT). It can serve either as a starting point for an upstream version or as the basis for the API shape.

Alternatives

• A single user-stylesheet setting: less discoverable, no live preview.
• Per-plugin themes only: fragmented and inconsistent between plugins.