body {
    margin: 0 auto;
    max-width: 400px;
    background-color: black;
    color: white;
    text-align: left;
    font-family: Arial, sans-serif;
}

h1, h2, h3, h4, h5, h6 {
    text-align: center;
}

h1 {
    font-size: 2rem;
}

@media (max-width: 1200px) {
    body {
        margin: 16px;
    }
}