body {
    font-family: monospace;
}

img {
    max-width: 100%;
    display: block;
    margin: 0 auto;
}

pre {
    overflow-x: auto;
}

article > header {
    text-align: center;
}

article {
    overflow-wrap: break-word;
}

nav {
    border-bottom: 1px solid;
    padding-bottom: 0.5rem;
}

body > footer > p {
    border-top: 1px solid;
    padding-top: 0.5rem;
}

body > footer {
    text-align: center;
}

body > header,
body > main,
body > footer {
    max-width: 768px;
    margin-left: auto;
    margin-right: auto;
    padding: 0 1rem;
}

body > header {
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
}

@media print {
    body > header,
    body > footer {
        display: none;
    }
}