Note that if you are using an older webkit browser, this problem of not-resizing may occur indeed. See this post. (Scroll to "Bugs!")
The support is there in Chrome 20+ / Safari 6+, but it fails in one
rather significant way. When the browser window is resized, the font
doesn't adjust itself according to the new viewport size. The spec
says:
When the height or width of the viewport is changed, they are scaled
accordingly. I bugged it. Perhaps not a huge disaster as it's pretty
much just us design nerds that go around adjusting browser windows,
but still. The font does adjust on a fresh page load.
To fix this issue (allow resizing without page refresh) you need to
cause a "repaint" on the element. I used jQuery and just fiddled with
each elements (irrelevant, in this case) z-index value, which triggers
the repaint.
causeRepaintsOn = $("h1, h2, h3, p");
$(window).resize(function() { causeRepaintsOn.css("z-index", 1); });
UPDATE: Don't worry about this anymore and definitely don't be forcing
those repaints. This resizing issue is fixed in Chrome 34+ and Safari
7+. It's not common to change the viewport size on mobile devices, so
I'm not sure if this bug ever effected them or not.