---
title: Documentation
---

Sass is a stylesheet language that's compiled to CSS. It allows you to use
[variables][], [nested rules][], [mixins][], [functions][], and more, all with a
fully CSS-compatible syntax. Sass helps keep large stylesheets well-organized
and makes it easy to share design within and across projects.

[variables]:    /documentation/variables
[nested rules]: /documentation/style-rules#nesting
[mixins]:       /documentation/at-rules/mixin
[functions]:    /documentation/functions

* If you're looking for an introduction to Sass, check out [the
  tutorial](/guide).

* If you want to look up a built-in Sass function, look no further than [the
  function reference](/documentation/functions).

* If you're calling Sass from JavaScript, you may want the [JS API
  documentation][js].

* Or the [Dart API documentation][dart] if you're calling it from Dart.

* Otherwise, use the table of contents for the language reference!

[js]: https://github.com/sass/node-sass#usage
[dart]: https://pub.dartlang.org/documentation/sass/latest/sass/sass-library.html