Save The Bandwidth, Shrink The Style Sheet
Depending on how many notes or modifications you make to your website css style sheets, you may need compression. By shrinking you external CSS files, you can save the bandwidth to download them, each time someone visits your web site.
Now how much optimization should you do? The CSS files should be small enough to be loaded quickly, but readable enough. You have to balance size with readability.
Three effective online tools to help optimize and shrink CSS files: