rem

The rem CSS length unit is a font-relative length that is equal to the font size of the root HTML element which for most browsers is 16px. To learn more, see <length> at MDN.

Compatibility (view on caniuse.com)

• Chrome 4 Released on 2010-01-25
• Chrome Android 18 Released on 2012-06-27
• Edge 12 Released on 2015-07-29
• Firefox 3.6 Released on 2010-01-21
• Firefox for Android 4 Released on 2011-03-29
• Safari 5 Released on 2010-06-07
• Safari on iOS 4 Released on 2010-06-21