This is an extension for Google Chrome
This extension allows you to change many websites design and color, based on a chosen preset, which are all user made, making it useful to browse on the internet with dark themes.
Furthermore, on the contrary to its old rival Stylish, it will not spy on your data and it automatically updates your downloaded themes.
As a courtesy I include a downloadable link which already includes a lot of themes for most of popular websites. All you have to do is go in the Stylus options and import the downloaded .json file.