       padding: 0;
        }

        body, #cover {
            height: 100%;
            width: 100%;
        }

        #cover {
            background-color: green;
        }
    </style>
</head>

<body>
    <div id="cover"></div>
    <script src="/resources/testdriver.js"></script>
    <script src="/resources/testdriver-vendor.js"></script>
    <script>
        document.addEventListener("fullscreenchange", () => {
            document.documentElement.classList.remove("reftest-wait");
        });
      