For PC users, go to your version (your own username and current app version) of
C:\Users\username\AppData\Local\slack\app-3.1.0\resources\app.asar.unpacked\src\static
Note that if your slack client updates (it does this quietly without telling you), you'll need to do this process again for the updated version.
For Linux users, using the slack desktop (beta) navigate to /lib/slack/resources/app.asar.unpacked/src/static
Mac users, go to your version of
/Applications/Slack.app/Contents/Resources/app.asar.unpacked/src/static
open ssb-interop.js with your editor of choice.
Add this code to the end of ssb-interop.js and save:
document.addEventListener('DOMContentLoaded', function () {
$.ajax({
url: 'https://raw.githubusercontent.com/earlduque/Slack-Dark-Theme/master/dark.css',
success: function (css) {
$("<style></style>").appendTo('head').html(css);
}
});
});
close and reopen slack
Further, I like this as the sidebar coloring:
on the channel list at the top, click on your name and go to preferences
click on sidebar
scroll down and click on advanced/custom theme
paste this into the custom theme input box:
#363636,#444A47,#D39B46,#FFFFFF,#434745,#ffffff,#99D04A,#DB6668