IE
31 stylesheets problem (KB262161) - STILL NOT FIXED in IE9
There was a known problem with Internet Explorer that it will only handle 31 style sheets.Above that it simply discards the styling information. And that really effs up a Drupal based site that doesn't have 'Optimize CSS files' set to enabled. AND the problem is still there in Internet Explorer version 9. I do not believe it!
More problems with Drupal optimised style sheets
Some time ago I experienced the well documented but little known (does that make sense) problem whereby IE can't handle more than 31 style sheets. Since I don't often use IE that's not much of a problem for me. But that's not really the point is it? The Drupal workaround is to optimize the style sheets. It does this by combining the sheets into one big file and serving that from a different CSS directory ( sites/default/files/css ).
I just re-enabled optimisation and noticed I've got a couple of new problems to solve.