Freeware and Online CSS Optimizer Here's a cool Cocoa app that shrinks your CSS down as small as possible. Non-Mac users can use the online tool, but there's also a Cocoa app for Mac OS X and a command-line utility for Mac OS X or Linux. In my tests, it works well unless you've stupidly (like me!) put a lot of php code in your css file! The developer also has an online un-optimizer tool that will make your CSS readable again.