Darker Medium applies a customizable dark theme to *all* medium formatted stories. You can customize the header background, main accent color, highlight color and link styles separately from the option menu. No matter the domain, if a site is using Medium, it will get a dark theme; that is the main advantage over Stylus and Stylish.
Apply a dark theme to Slack for Mac ⚫️ ✨
Sblack is a little free Mac app that applies a Dark Theme to Slack for Mac to make it easier on your eyes. Just drag and drop and you're done!