CSS3 Please! The Cross-Browser CSS3 Rule Generator
This page is a CSS3 reference tool that demonstrates how to implement modern CSS features with proper vendor prefixes for cross-browser compatibility. It provides editable code examples for common effects like rounded corners, shadows, gradients, transitions, and animations, allowing developers to see live previews while experimenting with values. The tool notes that Autoprefixer is now the recommended approach for handling prefixes, making this resource primarily valuable as a historical reference or learning tool for understanding which browsers required specific prefixes.