I tried last week each n every second to find that kind of template :-( ;-(
all six hundred and four thousand, eight hundred of them!?! (@_@)
joking aside, yeah, css isn't hard. But you need to think about layout, too, not just colors - do you want a single column? two? sidebar? If you find a template with a layout that you like, rewriting the stylesheets to have a simple, clean appearance would be a good way to start learning.