html {
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2rem;
    user-select: none;
    -ms-user-select: None;
    -moz-user-select: None;
    -webkit-user-select: None;
}

form {
    font-size: 0.5em;
}

.back {
    font-size: 1rem;
}