I use mixed mode: editor and terminal on black background (and US keymap) everything else on white background (and my country keymap.)

There is no particular reason for that except habits. I started programming on black background terminals and the first anything else happened on Unix workstations or Windows PCs with white backgrounds.

I adjust the overall brightness of my screen according to the light level of the room and I use night mode. When I happen to use some other computer in dark mode it's usually too dark: white characters are often too thin and don't enjoy enough light to be readable. Maybe dark mode is for young eyes or for people that are very sensitive to glare.