[triggeredcode]

Closes #72.

What changed

• Reworks the “Engineers think in structure” visual so one spoken thought is visibly separated into connections, dependencies, and decisions.
• Replaces the small architecture sketch with a clearer labeled request-flow diagram and a separate decision block.
• Adds a restrained semantic palette for structure, data, and decisions in both light and dark themes.
• Keeps the layout responsive and adds WCAG contrast regression checks for the new tokens.

Validation

• pnpm exec prettier --check site/index.html site/style.css apps/desktop/electron/site.test.ts
• pnpm exec vitest run apps/desktop/electron/site.test.ts — 31 passed
• pnpm exec eslint apps/desktop/electron/site.test.ts
• node scripts/build-site.mjs
• Visually checked desktop light/dark and a 390 px mobile viewport

The repository-wide lint command could not be used from this isolated clone because its dependency links do not reproduce the full workspace package graph; targeted lint for the changed TypeScript test passes.