Separate Category styles

Hi all! I’ve been looking for more information on HOW to develop the CSS/PHP for having a different style on each (or at least, most) of my different categories.

Example: on my original site, I had a different header/color palette for each of my main areas: Main, Remodeling, TKD, Family, etc…

I’d like to do that with my WordPress blog, but am unsure how to do it. I have already read through the ‘Theme Development’ info and saw the ‘Query-based Templates’ text. But, it looks like I need a template called ‘category.php’ in my files… which I don’t see in either of the default templates.

Can anyone offer som information or point me in the right direction?
Thanks!
Jberglund