Font size is actually the same as all the other 'new-style' pages (which is more and more of the site) - there's also more padding, too, which may be tweakable. I'll also contemplate if there's a way to make a better expand target for messages (particularly in conjunction with the old 'clicking anywhere on a message checks it' behavior, because that would have otherwise been my first go-to for expand/collapse...)

The weird mid-word breaks will also get addressed!