WebKit to get CSS variables, mixins, nesting?

I wonder, why introduce (yet) another syntax, not <style type="text/x-sass"> (or text/x-less) support. The latter can be used in supporting browsers natively, while there are existing JS helper libraries to provide support to other browsers.

Mixins seam the be the most useful feature to me, the other two seem more like syntactic sugar to me.

Strikes me as over complicated. Add variables to CSS. Done.