This document discusses various CSS3 features including border radius, transitions, transforms, multiple outlines, click through objects using pointer-events, custom input design using the :checked pseudo-class, sequential styling using pseudo-classes like :last-child and :nth-child, and creating background patterns with linear gradients. It provides examples and code snippets for each feature and discusses browser support, noting that many features have been supported by modern browsers for several versions but Internet Explorer only began supporting many features in version 10.