Sandbox Theme Center Menu Elements

The theme is here (the page is a live preview) http://www.plaintxt.org/themes/sandbox/

I've been trying with all mixtures of text-align: center; and margin: 0 auto; I just can't seem to move the elements of the menu into the center of the page.

Any help would be great :)

use a width:XXXpx (for example 800px) for div#menu ul and also set a margin:0 auto; to this. You have to set a width to center elements with margin:0 auto;