Overriding link sytle with class

I am trying to override a defined link style with a class, but it isn't working. Here is all of my relevant code:

From my style.css:

a:link {
font-weight: bold;
color: #ffffff;
text-decoration: none;
}

.hidden {
font-size: x-small;
font-weight: lighter;
color: #0033CC;
}

From my web page:

<p align="center"><a href="mylink.html" target="mainFrame" class="hidden">admin</a></p>

The font does come out x-small (the only aspect of the hidden class that is not in conflict with the a:link style, but it stays white and bold rather than blue and light. Is my code incorrect or am I misunderstanding how css works?

The page is http://www.wanderingjew.net (the "admin" link at the bottom left). It was designed in a combination of dreamweaver and textedit, and this problem is the same in all browsers (PC and mac) that I have tested it on.

Thanks!