html, body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}

  /* Per schermi grandi (desktop) */
  img {
    max-width: 450px;
    width: 100%;
  }

  /* Per dispositivi mobili */
  @media only screen and (max-width: 768px) {
    img {
      width: 90%;
    }
  }