CSS is a nice idea gone horribly wrong. It's a major pain in the butt to web content developers worldwide. I've been coding web apps for several years now and it still seems crazy to me! I am not a CSS fan and I am not alone.
So while I sit around and crib, people are coming up with extensions on top of CSS to alleviate the pain somewhat. All of them add support for nesting selectors which is something that should have been a part of CSS spec to being with. In addition -
- HSS adds variables, block variables, single line comments and CSS validation. Built on top of Neko.
- CSS Dryer adds support for variables. Written in Ruby.
- Sass changes the syntax to be a bit more terse (by getting rid of all the braces), and adds variables, namespaces, arithmetic/string/color manipulation operations and a bunch of other things. Written in Ruby.
- CleverCSS adds support for variables, property groups, lots of arithmetic/string expression operators and a bunch of other things. Written in Haskell.