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Enable Facebook's native dark mode for Messenger.com
// ==UserScript==
// @name Messenger Dark Mode Enabler
// @namespace http://greasyfork.icu/en/users/717657-crborga
// @version 1.0
// @description Enable Facebook's native dark mode for Messenger.com
// @author crborga
// @match https://*.messenger.com/*
// @grant none
// ==/UserScript==
document.querySelector('html').classList.add('__fb-dark-mode');