I'm really getting into CSS, and since I have very little experience, I guess you'll notice too

Here's another question:

I added this pure CSS dropdown menu to my site, and after some tweaking I got it to work with background images:

http://www.galleons.it/sptest/

It actually works perfectly in all browsers. The only problem I have is with FF, where the menu works great, but the clickable logo above the menu is 'covered' by the <li> and/or <a>'s of the menu and partially not clickable anymore. You can see the 'covering' with firebug.

I tried adding some z-index, but that made no difference.

Any solutions?