[TheLastSuperman]

You can add in your own custom .css to additional.css then wrap it forum, top div code into bottom of navbar and the closing </div> in the footer template as seen here:
http://www.innovationbyinstinct.com/forum.php

I used images in my css for the rounded corners, the rest actually does not use the moz/webkit/radius I removed it all via some css so you can literally do what you want pretty much it's knowing what templates to edit and how to add your custom css to the style that takes a little finesse per say.