It’s important to compress your stylesheets before going live with a project, but it’s hard to find a good web-based option that doesn’t require you to install software or scripts on your computer.
Code Beautifier is based on CSSTidy, an open source project which makes executable and PHP script solutions available to users. It doesn’t, however, feature the script for public use on the web, which is where Code Beautifier comes in.
The site offers a range of options to give you control over the extent of the compression. Certain compression levels can break parts of your CSS, so be careful to check everything out afterwards. I found it didn’t like the use of Garamond via Typekit in one stylesheet and stripped it out, while leaving Proxima Nova via Typekit intact.