I prefer to use darker interfaces on websites during evenings. So I change the looks of many websites with Stylus.
I plan to rewrite Safari Stylish so it works on Safari 12.0 if no one else does it.
Below are themes I like using with it.
In the cases where there doesn’t exist a Stylus theme for a website, I sometimes use Nightlight Safari extension to have all websites have night mode with a toggle on/off switch. It works surprisingly well and helps when using the internet at night.