CSS is like any other 'code' ...... there's good and there's bad.In my experience, Firefox only interprets CSS correctly some of the time.
Some of my first attempts at CSS sites looked terrible in moz (they didn't look so pretty in IE either!) .... but once you learn the 'proper' way, moz browsers actually interpret CSS better than IE.
Many of the 'workarounds' in CSS are there to get IE to display properly.
I know that it's been covered in other threads ...... but CSS isn't just about meeting Accessibility Standards. There's no doubt in my mind, someday (soon) all sites will use CSS for layout as well as 'styling'.
Long, painful road though