Changes border-bottom color in specified selector on sites including a specific URL
// ==UserScript==
// @name Change Border Bottom Color
// @namespace your-namespace
// @version 1.0
// @description Changes border-bottom color in specified selector on sites including a specific URL
// @match *://vanced-youtube.neocities.org/2015/*
// @run-at document-end
// @grant GM_addStyle
// @license MIT
// ==/UserScript==
(function() {
'use strict';
// Add custom CSS to change border-bottom color
GM_addStyle('body { border-bottom: 3px solid #dd4b39 !important; }');
})();