body{font-family:system-ui,sans-serif;max-width:42rem;margin:0 auto;padding:1rem;line-height:1.6;color:#222}
header{border-bottom:1px solid #ddd;margin-bottom:1.5rem}
nav a{margin-right:1rem}
footer{border-top:1px solid #ddd;margin-top:2rem;font-size:.9rem;color:#555}