via ajaxian:

Rafael Lima took inspiration from 37 Signals browser selector idea and created it. “It” being a JS library that allows you to create browser specific CSS to be merged into your normal classes.

Example

You can prefix browser specific elements (available codes: ie, gecko, opera, konqueror, safari) and the library will make sure that the correct items are added in for a particular browser.

This can be considered cleaner than some of the really ugly hacks that you normally face.

PLAIN TEXT
HTML:

  2. type=“text/css”>
  3. .ie .example {
  4. background-color: yellow
  5. }
  6. .gecko .example {
  7. background-color: gray
  8. }
  9. .opera .example {
  10. background-color: green
  11. }
  12. .konqueror .example {
  13. background-color: blue
  14. }
  15. .safari .example {
  16. background-color: black
  17. }
  18. .example {
  19. width: 100px;
  20. height: 100px;
  21. }

CSS Browser Selector