Useful sites for CSS, browser support issues

Found today while searching for answers to some coding questions:

Unminify: It’s impossible to read minified CSS, JavaScript, etc. This site accurately reformats minified code for you, making it human-readable.

Can I Use … ? Find out which browsers fully or partially support any given front-end web technology (such as box-sizing: all browsers!).

Should I Prefix? For some CSS properties, we need to include extra versions for Chrome, Firefox, or both (using the prefixes -webkit- or -moz-) — find out which properties still need these.

DiffChecker: Compare two text files. The differences between the two files (even spacing and tabs) are shown clearly with side-by-side highlighting.