The Real Meaning of font-size: 60%
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 40%, we make both 40% shorter, and 40% narrower. The net reduction in visible area from specifying font-size: 60% is therefore 64%.
The quick brown fox jumped over the sleeping dog. 60%
The quick brown fox jumped over the sleeping dog. 100%
The quick brown fox jumped over the sleeping dog. 12px
The quick brown fox jumped over the sleeping dog. 20px
