CSS-in-CSS

lastmod 2026-11-10created 2024-03-092 edits

CSS-in-CSS is a term for writing styles in separate CSS files, in contrast to CSS-in-JS, which keeps styles inside JavaScript code. It includes plain CSS, preprocessors such as Sass, and CSS Modules, which prevent class name collisions. Having no runtime cost and being able to use the browser cache are what set it apart from CSS-in-JS.