PostCSS parses CSSCascading Style Sheets — the language for layout, color, and typography on web pages. into an AST, runs plugins (AutoprefixerA PostCSS tool that adds vendor prefixes to CSS — keeps stylesheets working across browsers automatically., cssnano, TailwindA utility-first CSS framework — compose designs from small classes instead of custom stylesheets.), and outputs transformed styles — a postprocessor pipeline that works with any preprocessor or plain CSSCascading Style Sheets — the language for layout, color, and typography on web pages.. It became the backbone of modern front-end builds, powering millions of weekly npmNode Package Manager — the default registry and CLI for installing JavaScript and TypeScript libraries. downloads through webpack, ViteA fast front-end build tool — instant dev server and optimized production bundling., and Create ReactA JavaScript library for building UIs — component trees and declarative rendering for the web. App.

PostCSS created an extensible plugin ecosystem for CSSCascading Style Sheets — the language for layout, color, and typography on web pages. transformation.

It separated CSSCascading Style Sheets — the language for layout, color, and typography on web pages. authoring from build-time transforms like prefixing, minification, and future syntax.