• A CSS reset that eliminates the discrepancies across browsers.
• A solid grid that can support the most complex of layouts.
• Typography based on expert principles that predate the web.
• Form styles for great looking user interfaces.
• Print styles for making any webpage ready for paper.
• Plugins for buttons, tabs and sprites.
• Tools, editors, and templates for every step in your workflow.

Within about an hour or so I pretty much had it down. Check out this quick-start tutorial and this more detailed one to get yourself going. It eliminates a lot of the repetitive CSS work you normally have to do for each new project you start and creating a standards compliant layout takes just minutes using their included CSS classes and “the grid”.