Menu horizontal position from the top

I can't find the code that positions the 'main-menu' below the logo. I am trying to move the main menu down about 75px from its current position to make room for the logo.

Also, I would like to center the words for the categories.


-----------

Also, what is the best way to center the 'top-menu'. I inserted this code at the bottom of the menu section of the style.css;

#menu-box { position:relative;
z-index:18;
padding:10px 140px 48px;
}

It seems to work.