This document discusses web design principles including unity, variety, balance, rhythm, scale, emphasis, simplicity, and combination. It provides examples of how Twitter uses unity through a consistent bird theme. Variety is used through changing colors to direct attention. Balance is created through symmetrical window positioning. Rhythm leads the eye through elements in the background. Scale adjusts map sizes based on land coverage. Emphasis highlights important links in orange. Simplicity only shows useful information. Combination incorporates variety in font size, balance of header/body text, emphasis from header scale, and rhythm from picture/text patterns in a simple layout using few colors.