Difference between XHTML Transitional and Strict, a handy reference.
On another note, I tidied up my style sheets for the same project. I don’t dip into css very much (especially not in my weblog), but I actually enjoy when I get an opportunity to do so. Especially now. 2 years ago I wrote a fairly simple css file for a site, and erratic browser compliance made it impossible to get it to look right. For this reason I used some tables where I needn’t have. When I tried revising it now, I found doing so was fairly painless; I think it’s because you can pretty much count on everybody having IE 6 or Firefox. Automatic updates is good for something, no?
Looking back at my simple style sheet, I found a lot of sloppiness. I left in a lot of styles I was experimenting with, and I didn’t do much commenting, and the styles weren’t described in any order, leaving me to have to figure out what was cascading into what. Reducing clutter in css really makes it easier to see problems.