.demo-class{position:absolute;left:0;right:0;bottom:0;top:0;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center;overflow-y:auto;max-width:100%;height:calc(100vh - 60px)}.demo-class .responsive-img{max-width:100%;height:auto;display:block;margin:0 auto}