Most font size in rem, others in em

[vbeauvivre]

It would be a great idea if font sizes were movable according to device AND zoom level on the browser.
I suggest usage of rem for font size, and some em for specific cases (like empowering content with «large» class).
body { font-size:62.5%; } can be added to simply value human understanding (16px => 1.6rem on most devices)

see http://snook.ca/archives/html_and_css/font-size-with-rem