Example? I've never seen CSS that wouldn't render properly on Firefox/Firebird/Mozilla/whatever that didn't have any errors.

Feast your eyes on this in both IE and Firefox. This differences are slight but they are there. I was forced to redesign the page several times due to the age-old IE/Netscape/Mozilla issue of window margin widths. Any absolute or relative positioning is going to render slightly differently in each browser, which sucks when you are shooting for precise placement.

Other differences include Firefox not rendering the disc in front of the description date, the jog in the line below the words 'quantity', 'price', and 'amount' and the wierd alignment of the John Doe information when viewing the print preview in Firefox.

If you can find the error in my CSS, I'd like to know it.