.viewport-autoplay video{
    width: 100%;
}
.viewport-autoplay.mobile video::-webkit-media-controls-start-playback-button {
    width:50px;
    height:50px;
    left: calc(15% - 25px);
    top: calc(75% - 25px);
}
.video-headline {
    font-size: 18px;
    display: none;
    margin-bottom: 10px;
}
.video-headline.mobile {
    display: block;
}