You can achieve it with Stylus overwriting the style of askubuntu.com with AskUbuntu-Dark-Theme
Go to https://askubuntu.com/
Cick on Stylus icon and Write style for askubuntu.com
Paste style dark and Override style for: askubuntu.com
Save and ejoy!
More instructions: Usercss Wiki
If you want a global dark mode use: UltimaDark
Note: if the ...
I wish that we would.
No matter the question, the user is asking to resolve something on their installation of a supported/unsupported version.
Given how much time is spent in the already over-stuffed review queues, requiring a supported version tag when creating a question could go a long way to reducing the number of questions reviewed.