Linaria is a zero‑runtime CSS‑in‑JS library that lets you write styles in familiar CSS syntax (with nesting, variables, and logic) and have them extracted into static CSS files at build time, giving you the benefits of CSS‑module tooling without any runtime overhead. It’s aimed at front‑end developers—especially React users—who want dynamic, prop‑driven styling while keeping the bundle size small and enjoying full CSS‑tooling integrations like linting, sourcemaps, and optional preprocessors.