What steps will reproduce the problem?

1. Browse to content page on doctype site using Firefox 3.0b5/Mac
2. Zoom in using View/Zoom/Zoom In (or Apple+)

What is the expected output? What do you see instead?

Nav and content "frames" get smaller and smaller and acquire
scroll bars (and blank section appears at bottom of page).   
Gets worse the more you zoom.

What version of the product are you using? On what operating system?

Firefox3.0b5/OsX


Please provide any additional information below.

Love the site.