I've come back after a lengthy time away and I notice that after logging in the forum reverts to my skin settings from, like, 2012, and I can't figure out how to change it to just be the forum default. Hopefully this is just something dumb and obvious and I'm being blind.
I assume you've already figured it out since you're on default.
Newish members can't change their theme at all though. It is being phased out.
New forum skins please!