body, html {
    margin: 0;
    padding: 0;
}
div#iframe {
    position: absolute;
    top: 0;
    bottom: 0;
    right: 0;
    left: 0;
    margin-top: 0px;
    border-top: 1px solid black;
}
iframe {
    position: absolute;
    top: 0;
    bottom: 0;
    right: 0;
    left: 0;
    width: 100%;
    height: 100%;
}