1. Download and install FireFox (if you don't have it already)
2. Install Firebug (an add on for FireFox)
3. Go to your site in FireFox, under Tools, start Firebug and Viola!
you can play with your css to your hearts content. In Firebug, you can select your css, then select the
element you want to change, and edit. Changes will be shown in real time without actually modifing the css, so
you can see if your changes give you the desired effect. Once satisfied, go to your real stylesheet and comit
the changes.
You can find FireFox and Firebug here.
www.mozilla.com/firefox
So if you use Firefox Browser with the Firebug plugin, you will be able to do offline analysis of your page -
including revealing and editing of styles.