th: 100%;
    /* A 1x1 white PNG. When html is inverted, this should make the effective background black. */
    background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC");
    background-attachment: fixed;
    background-repeat: repeat;
  }
</style>
<!-- No visible content needed, we are checking the background color via pixel matching the -ref file. -->
</html>
