C55: More Info?

I saw a PyCon09 keynote presentation (slides: http://www.slideshare.net/kn0thing/ride-the-snake-reddit-keynote-pycon-09?c55) given by the reddit guys, and in it they mention a CSS compiler called C55. They said it would be open sourced soon. It looks cool - does anyone have more information about how it works, why they created it (aside from the fact that CSS is a pain), etc...?

From stackoverflow

• Just from the talk, the main advantage over simply generating CSS from templates is that it allows nesting, which is conceptually a lot nicer to work with.

  So you could do something like this in C55 (obviously I'm kind of making up the syntax):

  div.content
  {
    color: $content_color ;
  
    .left
    {
      float: left;
    };
    .right
    {
      float: right;
    };
  };