This is a question for all of you webmonkeys out there (Chris, I’m looking in your direction): are there any tools to assist in CSS debugging? By ‘debugging’ I mean knowing which styles are affecting a particular part of the page, knowing the bounds of a particular element, etc. My usual method is to edit a style to have a border or background color so I can more easily see what’s going on, and this is inefficient, at best. Other times, I have no clue what is making a particular element look the way it does (e.g. having some offset), so I just hack around with negative margins and things like that until it looks right.

If there aren’t any tools, what are your strategies for editing and debugging stylesheets?