I used to tinker quite a bit with Cascading Style Sheets. I don't much anymore. Here are some experiments I did that may be of interest.
When CSS support was new in Microsoft Internet Explorer 3.0, I put together this reference which documents what portions of the CSS1 specification are supported in that browser. Nowadays it's pretty dated; but, since there still might be a few folks out there still trying to use CSS compatibly with IE 3.0 (my sympathies), I'm leaving this page online for the time being.