There’s a new spec in town and it’s all about units! Exciting! There are new unites including vi (1% of the viewports size in the root elements inline axis), vb (not the rubbish Aaustralian beer, but 1% of the viewports size in the root elements block axis), ic (average character fullwidth glyph), cap (nominal height of capital letters in the elements font), lh (line height of the element), lhr (same, but for the root element). There’s a bunch more too, go check it OUT.
An excerpt from Introducing CSS Values and Units Level 4