PostCSS is a tool for transforming styles with JS plugins. These plugins can lint your CSS, support variables and mixins, transpile future CSS syntax, inline images, and more.
PostCSS is used by industry leaders including Wikipedia, Twitter, Alibaba, and JetBrains. The Autoprefixer PostCSS plugin is one of the most popular CSS processors.
PostCSS takes a CSS file and provides an API to analyze and modify its rules (by transforming them into an Abstract Syntax Tree). This API can then be used by plugins to do a lot of useful things, e.g., to find errors automatically, or to insert vendor prefixes.
Support / Discussion: Gitter
Twitter account: @postcss
VK.com page: postcss
For PostCSS commercial support (consulting, improving the front-end culture of your company, PostCSS plugins), contact Evil Martians at email@example.com.
Read full docs here.