Never really thought of css as being advanced, I think its a mess myself..
It's still advanced tho! A bit curious about how similar XSL-FO and XPS are. XSL-FO has the advantage of being XML based and therefore extensible, compared
to CSS. On the other hand CSS could be seen as a DSL. The ideal is to be able to use whichever you like the most - so the extensible format when you need it and the DSL when you don't need extensibility. I wonder if there's already an Mgrammar for CSS.