.preview {
  cursor: pointer;
}
#preview-mask {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  z-index: 9999;
  display: none;
}
#preview-mask .preview-img {
  max-width: 90%;
  max-height: 90%;
  min-width: 30%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
#preview-mask .close-btn {
  position: absolute;
  top: 20px;
  right: 20px;
  color: white;
  font-size: 30px;
  cursor: pointer;
}