Aside from the Stylish Firefox Add-on (which I have NOT yet installed because of the large number of thumbs-down reviews of the newest version), there doesn’t seem to be a viable way – AFAIK – to implement user stylesheets in Firefox (Windows). I’m flabbergasted by that, so much so, that I figure I must be missing something.
The userContent.css option isn’t a good one, because it appears to disable author stylesheets entirely.
Even IE6 allows one to apply user stylesheets!
I should correct myself: the Web Developer Toolbar DOES offer the use of a user stylesheet. In my (brief) experience, however, I must RE-choose the user styleseet I want whenever I move to a new page (even of the same Web site), even if Persistent Features is checked. I’m thinking there should be a simpler way…