cssdb is a comprehensive list of CSS features and their positions in the process of becoming implemented web standards.
Did you come here to update the status of a CSS feature or add a new one? Quick, read CONTRIBUTING.md.
Did you come here to learn about the stages? Quick, read STAGES.md.
cssdb ranks CSS features by stages that reflect the real-life stability of new CSS features.
You can read an inside view of the CSSWG to learn about the official (and unofficial) development stages of CSS specifications. In reality, specifications and browser implementations happen out of sync. For example, there are stable CSS features missing in all browsers, while other CSS features developed outside the CSSWG have appeared in browsers behind flags. This is too ambiguous for the web development community, and a more accountable process is desired.