That looks right to me. What you can do is take a look at the page after it renders use whatever browser tools you have available. (I prefer Firefox with the Firebug plugin.) That will tell you if the classes are being applied at all, and if they are, what styling is being applied.
It's also possible that your browser is caching the style sheet. In that case, a Ctrl-Refresh or Alt-Refresh, depending on the browser, usually forces it to reload.