Embarrassingly dumb question: if you’re one of the few users who don’t run a dark background terminal … how well do these TUI render (in a light background)?

Not a dumb question at all. I grew up using actual green screen terminals, and the advent of high-resolution colour monitors and applications with dark text on a white background felt like a blessing. I truly do not understand the regression to dark mode. It's eyestrain hell for me.

Unfortunately, I was unable to test in my light-background terminal, since the application crashes on startup.

If I'm working in a dark room, then light mode is eye strain hell. With dark mode, the minimum brightness I can achieve is about 100x lower than with light mode.

OLED monitors will bring green screen terminals back in style quite soon (with occasional orange and red highlights for that Hollywood haxx0r UX effect)

The worst is when you're in dark mode and suddenly open a website or PDF that's pure white. Instant flashbang.

I thank Apple every day for adding dark mode to the native PDF viewer for this exact reason.

My personal experience is mixed. Half the time, I get something usable, the other half I get something that prints light yellow on slightly-darker yellow or highlights an item with a dark blue background and dark green text. I'm sure there's something I can tweak in my terminal app to fix this, but it's easier to just avoid those apps.