CSS3 introduces a few new units, including the `rem` unit, which stands for *"root em"*. The rem unit is relative to the font-size of the root element `<html>`. That means that we can define a single font size on the root element, and define all `rem` units to be a percentage of that. The typography has `font-size` defined in 1.6rem (16px) and `line-height` in 1.6 (24px). Milligram uses the `font-family` [Roboto]( https://www.google.com/fonts/specimen/Roboto), created by Christian Robertson, and provided by Google.