#modal_wrapper.overlay::before {
    content: " ";
    width: 100%;
    height: 100%;
    position: fixed;
    z-index: 100;
    top: 0;
    left: 0;
    background: #000;
    background: rgba(0,0,0,0.7);
  }

  #modal_window {
    display: none;
    z-index: 15000;
    position: fixed;
    left: 50%;
    top: 50%;
    width: 970px;
    height: 480px;
    overflow: auto;
    padding: 10px 20px;
    background: #fff;
    border: 5px solid #999;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
    overflow-y:hidden; 
  }

  #modal_wrapper.overlay #modal_window {
    display: block;
  }