Chrome also has a functional adaptive dark mode (no extension required!), but it is hidden behind an experimental flag `enable-force-dark` as an origin trial on desktop. I am surprised that the Chrome team have not surfaced this to users earlier (outside of Android Chrome, where it is available as a 'Dark Mode' toggle).

To try it, go to chrome://flags and search for Dark Mode, then enable Auto Dark Mode for Web Contents.

Alternatively, you can toggle it on using the Chrome DevTools Rendering tab, as "Enable automatic dark mode"

Some pages break badly... like google docs and some QR codes