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title: CSS Pre-Processors
---
## CSS Pre-Processors

Pre-processor is a software that allows to use extended CSS functionality with variables, functions, operators and many more useful assets that plain CSS is missing.

## Popular Pre-Processors

* [SASS](http://sass-lang.com)
* [LESS](http://lesscss.org)
* [Stylus](http://stylus-lang.com)