.yvtwp-video-wrapper 
{
    position: relative;
    padding-bottom: 56.25%;
    padding-top: 30px;
    height: 0;
    margin-bottom: 10px;
}
.yvtwp-video-wrapper iframe 
{
    position: absolute;
    top: 0;
    left: 0;
    width: 100%!important;
    height: 100%!important;
}