Possible to limit Top Menu bar width?

Hello Milos, I was wondering if it is possible to limit Top Menu bar width so it does not auto expand to full computer screen width. I would like to see effect on my site with Top Menu bar only as wide as the existing menu tabs. On wider screens some have told me the expanding menu bar is a little distracting given my black and red colors. Please let me know if this modification is possible and I will try it out. Thanks again!

Please edit file template_css.php and find .topmenu_wrap. Then, change margin to margin:0 auto; and add width:900px; (you can use any value).