iframe {
    border: none;
    position: absolute;
    top: 50%;
    left: 50%;
    width: 70%;
    height: 70%;
    transform: translate(-50%, -50%);
}
html.b {
    background-color: rgb(102, 69, 16);
}
html.l {
    background-image: url('birthday/lion.jpg');
    
}