CSS-in-TS

cssints is compile-time CSS-in-TypeScript. You write calls such as css.flex().alignItems("center"). A Vite plugin runs them at build time and replaces each one with atomic, content-hashed class names in @layers. Nothing of the styling code ships to the browser except cx and the few lines behind cv, which join class names.

• Values are checked against the spec grammars (mdn-data) in the types and again at build time. A typo is an error in the editor and in the build.
• Conditions (media, container, supports, hover), variants (cv), design tokens and themes (createTokens, createGlobalTheme, check.contrast) are all build-time, and all typed.
• LightningCSS optimizes the output. Browser support (@mdn/browser-compat-data against your browserslist) is reported as warnings, except for what LightningCSS lowers for those targets.

Status: 0.1 is not published yet. Decisions and findings are in docs/wayfinder.md; the API reference is docs/API.md. Both are also a site with search and type hovers: apps/docs (cd apps/docs && bun run dev); deployed to Cloudflare with Alchemy: https://cssints.dev.