html,body{
    margin:0;
    padding:0;
    overflow: hidden;
    width: 100%;
    height: 100%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
  -webkit-box-direction: normal;
    -ms-flex-direction: row;
    flex-direction: row;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
            align-items: center;
  }