Thanks, I needed this! Always jarring at night, when you've got most everything in dark mode, and you go to some website and get blinded by the light.
I just installed the Chrome version of Dark Reader, and most sites are now in dark mode, but ironically, the Chrome store site for Dark Reader is still rendered in light mode: https://chromewebstore.google.com/detail/eimadpbcbfnmbkopoojfekhnkhdbieeh
Can't seem to find a Dark Reader setting to flip it to dark.
I actually got an email from someone at Discourse who explained that it is actually possible to add theme components to the forum. I just did this and so you should now see the / toggle in the top right corner of the screen. It's also supposed to automatically switch depending on your computer's preference but I haven't tested this yet.