.overlay {
  width: 100%;
  height: 100%;
  background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQAQMAAAAlPW0iAAAAA3NCSVQICAjb4U/gAAAABlBMVEXMzMz////TjRV2AAAACXBIWXMAAArrAAAK6wGCiw1aAAAAHHRFWHRTb2Z0d2FyZQBBZG9iZSBGaXJld29ya3MgQ1M26LyyjAAAABFJREFUCJlj+M/AgBVhF/0PAH6/D/HkDxOGAAAAAElFTkSuQmCC');
  overflow: hidden;

  img {
    display: block;
    max-width: 100%;
    max-height: 100%;
  }

  .close {
    position: absolute;
    top: 10px;
    right: 10px;
  }
}