CSS definitions after a history of editing and alterations especially can contain many errors or ambiguous / confusing definitions, and it combined with the HTML together to confuse browsers. Different browsers / different Gelko engine version responds differently to different confusions. So at time some problems are hidden until another new bowser shows some funny rendering of pages.
I got these before. When new browsers appeared in market some of pages that worked well for years, suddenly ran away and shifted. That was because CSS were supplied by some downloaded programs and I only modified it without fully reading it inside out. And after years, can not remember any shit any more. When bug appeared de-bug until Siao! :*:
