The idea of a dark mode for lobsters has been brought up in the past:
The recommended solution has generally been to use a user style. That’s a great solution for desktop users, given you trust the Stylus extension. However, it leaves mobile browsers without any options. Now, given that both iOS and Android have implemented OS-level dark modes, it seems like a feature worth adding to the site.
This could be done seamlessly using the prefers-color-scheme CSS feature; both Android and iOS browsers support this feature. A boolean setting could be added to the user profile page as a fallback option.
As for the design of the scheme, it might be enough to integrate an existing popular user style into the site.
Is this a feature you would appreciate if it was implemented?