The Real Meaning of font-size: 70%
CSS font "sizes", for simplicity, refer only to height. However, everything we see on a computer display has two dimensions, height and width. Any text we reduce by 30%, we make both 30% shorter, and 30% narrower. The net reduction in visible area from specifying font-size: 70% is therefore 51%.
The quick brown fox jumped over the sleeping dog. 70%
The quick brown fox jumped over the sleeping dog. 100%
The quick brown fox jumped over the sleeping dog. 14px
The quick brown fox jumped over the sleeping dog. 20px
