When I\'m working with CSS, I\'ll often test in a browser - say, Chrome - right click an element, click Inspect Element, and edit the CSS right there. The use of arrow keys
I've suggested this product on SO before (I'm not affiliated with them in any way).
http://www.skybound.ca/
Excellent product. Sounds like exactly what you're looking for and much more.
EDIT: Several other answers here have mentioned Google Chrome's ability to link to your local files (which is very very cool). Check out the other answers!