body {
    background-color: #eee;
    background-repeat: no-repeat;
    background-size: cover;
}

#middle {
    background: rgba(0, 0, 0, 0.2);
    color: white;
    font-size: medium;
    border-radius: 1rem;
    padding: 1rem;
    position: absolute;
    left: 50%;
    top: 40%;
    transform: translate(-50%, -50%);
    text-align: center;
    width: 40%;
}