The builtin nixos documentation is blinding and bright I could easily help develop dark mode for it as I have with much more complex projects (the cayman and minimal jekyll themes) and the styles are really simple. If I know where all the code is kept for these builtin docs I can create a PR
nixpkgs/doc at master · NixOS/nixpkgs · GitHub - not particularly hard to find
That said, there is already work underway to move it to this, which does respect the browser settings: Preface | nixpkgs
@ryantm might know more about the state of it.
It’s basically about the same as what you see there. I’ve worked on it off and on but haven’t really been able to focus on it lately.