[triggeredcode]

Closes #74.

What changed

• keeps the editor and reading surfaces neutral
• uses blue for structure/input, violet for commands and AI context, green for decisions/success, and amber for clarification/attention
• applies the same vocabulary to the desktop app and GitHub Pages site in light and dark themes
• updates contrast and appearance coverage

Reversibility

This is a single isolated commit, stacked on #73. The tokens live in the light/dark theme blocks and the component overrides live in a clearly marked semantic-colour block at the end of each stylesheet. Reverting 3be03d2 restores the previous palette without touching markup, settings, documents, or the diagram work.

Validation

• 39 targeted Vitest checks passed
• semantic foreground/background and on-accent contrast ratios are asserted
• Prettier and git diff --check passed
• static site build passed
• website reviewed visually in the local browser

Full repository CI is expected to validate the normal workspace installation; this lightweight review clone uses linked dependencies, so its standalone full typecheck cannot resolve every workspace package.

[triggeredcode]

Implementation and validation are complete. Full GitHub Actions CI passed on Linux, macOS, and Windows, including typecheck, lint, format, and unit tests. This remains intentionally stacked on #73 so either visual change can be reviewed and reverted independently.