need help with the CSS on my blog

i know i said that i would only write in spanish in this section.... but since i want to ask people for help, i figure i probably shouldn't lol i was looking at the documentation for this site and "class_names" has spiked my interest... okay, so i'm interested in changing the accent color on certain "sections" of my blog, and i imagine that it's likely i could do that with "class_names" (and if…