This excites me, some proposals for CSSOM (better CSS value access from the DOM), variables, modules and nesting. This means you’ll be able to do stuff like this:

@var header-color color #006;
@var main-color color #06c;
@var secondary-color color #c06;
a { color: var(main-color); }
a:visited { color: var(secondary-color); }
h1 { 
  color: var(header-color);
  background: linear-gradient(left,var(main-color), transparent 25%);
}

See the full presentation here: http://www.xanthir.com/talks/2011-01-12/slides.html

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via Tab Atkins Jr. member of the CSS3 working group.