puzzlepeaches

// Mozilla User Preferences
// To change a preference value, you can either:
// - modify it via the UI (e.g. via about:config in the browser); or
// - set it within a user.js file in your profile (create it if it doesn't exist).
//
// Profile folder location on different systems:
// Windows: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\xxxxxxxx.default
// Mac OS X: Users/<username>/Library/Application Support/Firefox/Profiles/xxxxxxxx.default
// Linux: /home/<username>/.mozilla/firefox/xxxxxxxx.default

puzzlepeaches

1. Close slack
2. Open this file /Applications/Slack.app/Contents/Resources/app.asar.unpacked/src/static/ssb-interop.js
3. Append this to it

document.addEventListener('DOMContentLoaded', function() {
 $.ajax({
   url: 'https://cdn.rawgit.com/laCour/slack-night-mode/master/css/raw/black.css',
   success: function(css) {
 $("").appendTo('head').html(css);