@media only screen and (min-device-width: 320px) and (max-device-width: 768px) {
  .pop-up-qr img {
    width: 90%;
    height: auto;
  }

  .title h1 {
    width: 100%;
    text-align: center;
  }

  .content {
    background-size: cover;
    padding: 20px;
  }
}