This is a couple of neat scripts that will theme slack (OSX only currently).

To theme your Slack run the following command:

yarn install-theme <theme-name>

-- or --

npm run install-theme <theme-name>

To un-theme your Slack run:

yarn uninstall-theme

-- or --

npm run uninstall-theme

The available themes are:

• dark
• one-dark
• low-contrast
• navy

To add your own themes, add an entry to the themes.json file in the themes folder.

The code for this was borrowed from https://github.com/widget-/slack-black-theme and is mostly just an installer/uninstaller for that.