Style sheets do two things:
It's important to use H1, H2, H3, H4 etc. to indicate the organization of your page
Here's what the headings look like:
"Normal" is the style used for regular paragraph text.
You will see a number of other styles that were created for the dropdown menus and the footer of all the pages on the site. Below are styles you should are free to use:
centered (centers text, if you must)
invisible (can't really show this one!)
textintables (modified whitespace surrounding paragraphs in table layouts)
All styles can be applied to paragraphs, list items, words and phrases. All can be used in addition to bold and italics.
Same list with "nobull" list style: