Viewport sized CSS unitsEdit
These are new units added in CSS3:
vw:1vwequals 1% of viewport widthvh:1vhequals 1% of viewport heightvmin:1vminis1vwor1vh, whichever is smallervmax:1vmaxis1vwor1vh, whichever is larger
Support for these units isn’t so great — see http://caniuse.com/#search=vh — at the moment. Chrome, Firefox et al are good, but IE only has proper support from IE 11 onwards.