User blog comment:Susanolivia/Beta Wrap-up/@comment-28861328-20101006184927/@comment-93604-20101006213235

Please see:
 * http://www.456bereastreet.com/archive/200504/about_fluid_and_fixed_width_layouts/

It uses a maximum fixed-width layout (content space), but that fixed width increases for larger text sizes picked in browser options. Try it and see.

The CSS uses em units instead of pixels to measure the width. See: http://en.wikipedia.org/wiki/Em_%28typography%29