To me, the biggest issue with dark mode is that it doesn't differentiate between chrome and content. Dark chrome helps light content pop, reduces distractions. Unfortunately, the moment one turns it (dark chrome) on, the content goes dark too. Depending on your eyesight, you might be OK. I for one can't look at dark content in light ambient conditions for longer than few minutes without discomfort.
- Base background: white or slightly off white -> a dark enough grey or off-grey for good baseline contrast
- Borders: darker on the grey scale -> dark enough to strongly contrast the base background, or omitted for bordered areas which are already that dark
- Toolbars, window handles, other concrete “chrome” areas: darker than baseline, for both light and dark modes
- Buttons and text: high contrast, dark in light mode, light in dark mode
- Active items: accent color or outline for maximum contrast
- Colors generally: the same hues except when other color perception preferences are chosen (for either mode), but generally a slightly lower saturation for dark mode backgrounds, and hue adjustments for color perception errors in color spaces
All of this in my experience needs a lot of eyeballing but quite a lot could probably be approximated with good perceptual light and color models. But I’ll still prefer light mode most of the time.