Because it turns out that while this might sound like the easy, simple, convenient, right thing to do, if you try it (as we did), what happens is that people wi

Because it turns out that while this might sound like the easy, simple, convenient, right thing to do, if you try it (as we did), what happens is that people will forget or not understand they set it, and be unhappy and complain: https://gwern.net/design-graveyard#auto-dark-mode https://gwern.net/design-graveyard#auto-dark-mode (You can do the fallback to the CSS prefers setting, to try to not break dark-mode users, but if at all possible, you do want some sort of widget or toggle - at least for now. I am hopeful that in maybe 5 years it can be removed and users assumed to understand it.)