GitHub has a new dark mode that can be enabled as a user preference. See https://betanews.com/2020/12/08/github-dark-mode/
Unfortunately, GitHub does not seem to automatically detect when the web browser or OS are set to a dark mode or theme. Thus, the dark mode does not ever get applied when you are not logged in.
Is there a way to enable the GitHub dark mode when you are not logged in? Specifically, I'm thinking of a URL parameter that can be added to any github.com URL, but I am open to all answers.