This might be captain pædantry to the rescue, but that spans are inline-level has little to do with this. The fact that most (all) browser's house-style sheet implicitly sets the span's property on display:inline
does unless the author or the user explicitly overrule this does though. As far as I know, the W3C does not define what the house style of browsers must be, but they do give some pointers for interoperability.
Of course, this might not be as relevant here, but there are actually some places where browsers don't pick their styles all the same. Notably Safari and Chrome do not place a dashed border under abbr
by default while Firefox and IE do. Also, some browsers space paragraphs by using margin-top:1em;
while others use margin-bttom:1em
, in most cases this doesn't matter but there are some cases where defining explicitly which of the two you want in your site is in fact needed for a consistent look.