.embed-responsive {
    position: relative;
    display: block;
    height: 0;
    padding: 0;
    overflow: hidden
}
 
.embed-responsive .embed-responsive-item,.embed-responsive iframe,.embed-responsive embed,.embed-responsive object,.embed-responsive video {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0
}
 
.embed-responsive-16by9 {
    padding-bottom: 56.25%
}
 
.embed-responsive-4by3 {
    padding-bottom: 75%
}