PostCSS

A List Apart: What Will Save Us from the Dark Side of CSS Pre-Processors

difference between PostCSS and CSS pre-processors

In contrast to pre-processors’ distinct syntaxes, post-processors typically feed on actual CSS. They can act like polyfills, letting you write to-spec CSS that will work someday and transforming it into something that will work in browsers today. Ideal CSS in, real-life CSS out.