User blog comment:Sannse/Your First Look at the New Wikia/@comment-1514297-20100830123331/@comment-824313-20100830131452

It probably has a set width for the content area, so the screen can get smaller and all that shrinks is the empty space.

By the way, that "empty space" could probably be put to use by adding a non-repeating BG image with information (like a sticky-note type thing.)