One of the most powerful features of the CSS preprocessor Sass is the mixin, an abstraction of a common pattern into a semantic and reusable chunk. Think of taking the styles for a button and, instead of needing to remember what all of the properties are, having a selector include the styles for the button instead. The button styles are maintained in a single place, making them easy to update and keep consistent.

prepackaged patterns and components, built on top of Bourbon, Bitters, and Neat.

HTML5 framework, WAI-ARIA roles and HTML5 semantics
   Baseline HTML5 features, DNS prefetching, responsive meta
   Encourages one-file CSS/JS in the view (HTML) for performance
   Includes jQuery CDN and relative fallback
   Includes Modernizr and HTML5 Shiv
   Google Universal Analytics snippet
   Open source workflow with Grunt.js running on Node.js
   A grunt.command file for double-click command-line execution
   Automatic Grunt dependency installation, directory relocation and grunt tasks
   Dynamically appended copyright for JS/CSS
   Livereloading the browser and file injection upon changes
   Annotated Gruntfile.js for extending
   Built-in build script for auto-minification of CSS and JavaScript files for production
   Pre-setup Sass/SCSS files and folders for baseline project structure and imports
   Includes .editorconfig for consistent coding styles in IDEs
   Standard .gitignore to ignore minified files and standard ignorables such as .DS_Store
   JSHint .jshintrc file for configuring JavaScript linting
   No superfluous code comments

alternativ:
http://www.phpsass.com/
http://leafo.net/scssphp/

Groundwork is a responsive HTML5, CSS and Javascript framework.