actually it doesn't work in ie7 for me.
Your code desperately needs attention!
You start off with a head section which is fine.
Then you open your body section. ok.
Then you open another head section inside the body section. NOT GOOD!
Then you close it. PHEW!
Then you open ANOTHER body section?
Then you close it to open another head section?
Then you close 3 body sections....
And to be honest, I give in.... lol
Where you've specified the width of the li to be 10em, change that to something like 200px (do the calculations to work out what will take the menu right the way across the top, or use trial and error).
Then I'd suggest you go to www.w3schools.com to learn about html - you should have one head section, containing all your css and scripts. Then you should have one body section containing all the page contents.
I'm sorry that this has turned into a bit of a negative post, but whilst your design looks like it could be really good once you sort your code out, at the moment your code is really letting it down.