PostCSS – A Comprehensive Introduction — Smashing Magazine

One of the relatively recent tools introduced for styling is PostCSS, which aims to reinvent CSS with an ecosystem of custom plugins and tools. Working with the same principles of preprocessors such as Sass and LESS, it transforms extended syntaxes and features into modern, browser-friendly CSS. Over the next few years, the way you use CSS will change in many different ways. Every project will have different requirements, to which you will have to adapt your production methods. Working within a modular ecosystem like PostCSS allows you to pick and choose the features you want to complete a project.