body {
    background: whitesmoke;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 350px;  /* 100vh */
    flex-direction: column;
}

form {
    width: 500px;
    border: 3px solid gray;
    padding: 20px;
    background: rgb(247, 247, 247);
    border-radius: 10px;
}

h2 {
    text-align: center;
    margin-bottom: 20px;
}

img {
  max-width: 20%; /* Das Bild passt sich dem Bildschirm an (responsiv) */
}