A CSS Preprocessor is a tool which makes CSS powerful, flexible and easier to write. CSS Preprocessors adds new functionality to css such as variables, constants mixins and functions.
CSS Preprocessor Languages
Sass — is an extension of CSS3, adding nested rules, variables, mixins, selector inheritance, and more. It’s translated to well-formatted, standard CSS using the command line tool or a web-framework plugin.
LESS — LESS extends CSS with dynamic behavior such as variables, mixins, operations and functions.
xCSS — an object-oriented CSS Framework
CSS Preprocessors Applications
Simpless compiles less into Beautiful CSS
CodeKit helps you build websites faster and better. Its flagship features are listed below and the one-minute teaser video to the right is a good place to start.
Hammer is a web development tool for web designers & developers. Build out static HTML sites & templates quickly and easily. No fuss, no mess, no PHP.
Scout is a cross-platform app that delivers the power of Sass & Compass into the hands of web designers.
Prepros is a free and open source web design & developement tool that does all the heavy lifting needed to preprocess CSS , JS & Images and keeps your preprocessing workflow seemless.
Compass is a stylesheet authoring framework that makes your stylesheets and markup easier to build and maintain. With compass, you write your stylesheets in Sass instead of plain CSS.
WinLess is a Windows GUI for LESS.js. WinLess is a must-have for the web developer who uses Windows.
Koala is a GUI application for Less, Sass, Compass and CoffeeScript compilation, to help web developers to use them more efficient.Koala can run in windows, linux and mac.
LiveReload monitors changes in the file system. As soon as you save a file, it is preprocessed as needed, and the browser is refreshed. Even cooler, when you change a CSS file or an image, the browser is updated instantly without reloading the page.