[csswg-drafts] Pull Request: [css-fonts-4] Fix small font size

Alexendoo has just submitted a new pull request for 
https://github.com/w3c/csswg-drafts:

== [css-fonts-4] Fix small font size ==
Currently the text below 
https://drafts.csswg.org/static/css-fonts-4/#document-conventions is 
set to π% which is interesting, but particularly hard to read

See https://github.com/w3c/csswg-drafts/pull/431