How to remove space above (IE) or below (firefox) navbar (nice menu problem)

Anyone know how I can change the spacing above & below the navbar in zen?

Here is my problem: I want my navbar to be flush with the header and the content (i.e. no padding or margins above or below the navbar). If I decrease the height of the navbar (and make the corresponding change to the sidebar margin-top) I can eliminate the space below the navbar in firefox. However, in firefox there is still a space above, and in IE there is still a space below the navbar. If I make the height any smaller the navbar starts going behind the content. I can't find any property to eliminate that space.

My setup: I disabled the primary menu in the template and am using a block to show the primary menus. I am also using nice menus so I can do a drop down menu.

Any tips?

Thanks!