css and the_meta

Hi again,
I notice in the index.php that some of the elements have id’s associated with them, for instance <li id=”categories”>. I do not see any style rules named #categories in the style sheet however. Is this so I can create it myself and style away, OR is there something lurking below the php that I don’t see or understand?
Also (and perhaps this is linked to the above question??), what is the_meta?? “/* classes used by the_meta() */ “. The wiki is a bit bare on this one… I am assuming the classes that effect the UL and other elements in the categories and links are styled by this??
Thanks