Solution: Use the Raw Html Plugin which allows you to put html content on the wiki page.
<?plugin RawHtml Your HTML Here ?>
Example 1:
Using the RawHtml plugin you can take advantage of this cool align right yellow box thing. Simply make a div with a class of "note" and start it with an H2. ("Edit" this page if you don't follow.)
This page uses the RawHtml to create the yellow note to the right.
Example 2: Coloring using HTML and inline style (CSS)
Here is some embeded styling that makes the text of this paragraph red. (edit the page to see how it's done)
Example 3: Making text in a pink box with a border and such using HTML, a class attribute and a style block (CSS)