bbh-pc/iframe.css

#visiting{
    position:absolute;
    top:0;
    left:0;
    /* top:50%;
    left:50%;
    transform: translate(-50%,-50%);*/
    width:51.9rem;
    height:29.2rem;
    border-width:0;
    margin:0;
}

.test{
    position:fixed;
    top:50%;
    left:50%;
    transform: translate(-50%,-50%);
    width:51.9rem;
    height:29.2rem;
    /* background-color: lemonchiffon; */
}