Object-oriented CSS framework

xCSS bases on CSS and empowers a straightforward and object-oriented workflow when developing complex style cascades. Using xCSS means a dramatic cut down to your development time by: having a intuitive overview of the overall CSS structure, using variables, re-using existing style cascades and many other handy features. But, most frameworks are bulky and inflexible, aren't they? Not xCSS! It's lightweight and seamlessly integrates into any existing workflow. Aside from that the CSS overhead is getting reduced while your (X)HTML attributes remain semantic.

Source on GitHub