Liquid CSS layouts are fluid width designs. Some web developers consider the 'Holy Grail' of design as one that
- has a fluid center with fixed width sidebars,
- allows the center column to appear first in the source,
- allows any column to be the tallest,
- requires only a single extra div of markup, and
- requires very simple CSS, with minimal hacks patches.
See A List Apart: In Search of the Holy Grail to read the article. Mathew James Taylor accomplished just that with a light style sheet and markup. His designs are free and easy to interpret and modify. Enjoy.