vanilla‑extract lets developers write CSS in `.css.ts` (or `.css.js`) files using TypeScript, producing locally‑scoped class names, CSS variables, `@keyframes`, etc. All styles are evaluated at build time to generate static CSS files, so there’s zero runtime overhead and full type‑safety, making it suitable for any front‑end framework (or plain JavaScript) that wants a Sass‑like workflow with modern CSS features. It’s aimed at front‑end engineers who want a type‑safe, zero‑runtime alternative to CSS‑Modules or CSS‑in‑JS solutions.