It's that 30 point font that's blowing things out. I tried changing mine to 30 and it breaks a lot of sites in all browsers.

The overlapping here only happens with Safari though. Chrome and FF 3 and 4 don't overlap, but just like the screen shots you posted, in all browsers 30 does break the menus in the black bars at the top of the page, and jumbles up the bottom of the page.

FF has a setting in Content-Fonts under the Advanced button, to override page fonts or not BTW.