Different subject, and not specific to DokuWiki (sorry).
Your best bet is to
learn basic CSS - it'll only take a few hours at most. And you'll thank me when you find out what the C in CSS stands for when you look back at your question (H1 and H2 text-align).
You'll find
pseudo-elements deals with your contextual paragraph formatting question
Some useful tools are the Developer Toolbar (Inspector) and Firebug for Iceweasel/Firefox, Inspect for Google Chrome.