I realise this is a bit late in the game, but I've finally "learned" CSS. In quotes because I don't know an appreciable number of the available elements and, like probably a lot of people, I just cargo-cult around until I find something that works. My use of CSS is intentionally very miminal (see html version of this page).
It's amazing how easy it is to find bad docs about CSS still that encourage using absolute positioning, per-pixel layout, fixed page size, etc, and how hard it is to find answers to simple questions like "how do you embed a simple form in a horizontal list-based CSS navbar". Oh well..
I really hope that I'm about done with the web features side of ikiwiki, now that it uses CSS, is valid XHTML 1.0, and even has full text search thanks to Hyper Estraier.