body{
    margin:0px;
}
div#intro, div#outro{    
    max-width: 100vw;
    width:100vw;
    text-align:center;
    font-size:20px;
}
div#outro{
    display:none;
}
button{
    padding:10px;
    font-size:20px;
    font-weight:bold;
}
div#img-holder{
    /* Vertically center the div. */
    position:absolute;
    top:50%;
    transform:translateY(-50%);
    width:100%;
    text-align:center;
}
div#img-holder img{
    width:95vw;
}