body{max-width:720px;margin:0 auto;padding:1rem;font-family:sans-serif;line-height:1.5}img{max-width:100%}pre{background:#f0f0f0;padding:.5rem;overflow-x:auto}nav a{margin-right:1rem}footer{margin-top:3rem;border-top:1px solid #ccc;padding-top:1rem;font-size:.9rem}