zcorpan wrote:I think you're misreading the spec. The guess-work is only a hint that UAs can optimize their implementation, but the end result still has to be the same as if they followed the algorithm literally.
Yes I see your point. Then, evidently, Opera and Firefox think it is right to collapse the margin and IE does not.
and wrote:The point I was trying to make is that valid HTML 4.01 Strict can look very much like my initial code.
I don't think it "looks" like it , but I see now that FF creates the missing head and body elements (Opera doesn't create the head). I've learned quite a bit about HTML5 today. Thank you all for being patient with me.