Plain CSS with design tokens, small ES modules, and no client framework
Colors live only in src/assets/css/themes.css. A theme sets the base tokens listed there, and derived tones are computed with color-mix(). Add a theme by appending a [data-theme="name"] block. Fonts, spacing, and the type scale live in tokens.css.
No third-party requests (enforced by the CSP in src/_headers)