Your stylesheet has
Code:
/*the top toolbar*/
#navMainWrapper, #navCatTabsWrapper {
margin: 0em;
margin-bottom: 0px;
height: 30px;
background-color: transparent;
background-image: none;
background-repeat: no-repeat;
font-weight: bold;
color: #ffffff;
padding: 0px;
}
You have set a fixed height for the wrapper, but #navMain doesn't seem to need that much height, leaving blank space below it.
Either find the actual height of #navMain and use that, or eliminate the height altogether and let #navMain take what space it needs.