Here’s the thing. I’ve seen umpteen diagrams showing CSS beginners how padding, border and margin work together, but not the order in which elements such as background colour and image are stacked. To try and fill this hole, I’ve drawn a diagram. I’m not sure if this is of any use at all, but here it is anyway - the 3D CSS Box Model.
(Updated: 21.5.04): Added keylines to show ‘fitting’ and changed the background image to be more obvious. Others have now done their own versions, Tom has created a black & white printer friendly version and Douglas has created an interactive version - great work chaps.
There is now a French translation available here.