Code editor font size is ridiculously large

[PatchMixolydic]

Recently, the code editor's font size has become unreasonably large (other programs + address bar + "Run" button for scale):

(It's a little hard to tell from this screenshot; it looks much worse in person)

This makes it much harder to read (and therefore write) any substantial code examples in the Playground.

Seems to have been changed in e8f3cb1.