I would first make a distinction between CSS and UI design. You can make sucky UIs in CSS and you can make great UIs without CSS.
UI design is really more of a set of beliefs than coding.
Start by reading Defensive Web Design for the Web by 37Signals guys.
Jakob Nielsen's useit.com alertbox articles are a great place to start too-- http://www.useit.com/alertbox/ Back in high school I printed all his useit.com articles at the library printer and compiled it neatly in a binder:)
Also checkout Jakob Nielsen's Homepage Usability: 50 Websites Deconstructed.
UI design is really more of a set of beliefs than coding.
Start by reading Defensive Web Design for the Web by 37Signals guys.
Jakob Nielsen's useit.com alertbox articles are a great place to start too-- http://www.useit.com/alertbox/ Back in high school I printed all his useit.com articles at the library printer and compiled it neatly in a binder:)
Also checkout Jakob Nielsen's Homepage Usability: 50 Websites Deconstructed.