Information Architects have designed a custom, responsive typeface. Oliver Reichenstein explains:
So far, we only had a choice of a couple of system fonts, and there was not much to choose from. For serifed typefaces there was mainly one (Georgia) and for san serifed typefaces there were two or three (mainly Arial and Verdana). These typefaces were designed in the early nineties for what we now consider low resolution screens. They have worked beautifully until recently. Unfortunately, they don’t work on high density screens.