Guide to mastering CSS typography: choose and stack font-family with fallbacks and web fonts (e.g., Google Fonts), size text with px, em, and % using scalable relative units, and control emphasis via font-weight (100–900, normal/bold). Learn to combine properties (incl. line-height) for hierarchy, and follow best practices—limit to ~3 fonts, prefer relative sizes, and experiment for cohesive, readable UIs.