Although some sites provides a native dark mode that follows the OS settings. Others still dont. They provide a dark mode, but you have to manually select it. Others dont even provide one at all.
This is a collection of user styles to toggle dark mode when the system says so. Some are custom made, others are from the web, others are the one that the site provides but you have to toggle manually. All of them are edited to respect the
@media(prefers-color-scheme: dark) media query.
To use them you have to have an extension in your browser like Stylus (Chrome/Firefox)