.embed-responsive{
                position:relative;
                display:block;
                height:0;
                padding:0;
                overflow:hidden
            }
            .embed-responsive .embed-responsive-item,.embed-responsive embed,.embed-responsive iframe,.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%
            }