aws-console-color.user.js

// ==UserScript==
// @name         AWS Console Header Color
// @namespace    http://ryotarai.info/
// @version      0.1
// @description  Change color of header
// @author       Ryota Arai
// @match        https://*.console.aws.amazon.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    var role = document.querySelector(".awsc-switched-role-username-wrapper .nav-elt-label");
    if (!role) {
        var background = "#a00";
        document.querySelector("#nav-menubar").style.background = background;
        var e = document.querySelectorAll(".nav-menu");
        for (var i = 0; i < e.length; i++) {
            e[i].style.background = background;
        }
    } else {
        // role.title == "ROLE @ ACCOUNT"
    }
})();