html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
}
body {
    background: linear-gradient(to top right, #4400A6, #500026);
}

div {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}
h1 {
    margin: 0;
    padding: 0;
}