I've released a small PCalc 4.11.1 update that's out now for the Mac.

https://pcalc.com/store/pcalcmac

There was a bug with the theme getting reset, which I _could_ have fixed in five minutes, but I ended up doing what I should have done over three decades ago, and added a dedicated section to the settings that puts all the visual customisation in one place.

No more having to search for all this stuff in a submenu somewhere!