body{max-width:40rem;margin:2rem auto;padding:0 1rem;font-family:system-ui, sans-serif;line-height:1.5}header{border-bottom:2px solid #0a6}header nav a{margin-right:1rem}footer{margin-top:2rem;border-top:1px solid #ccc;font-size:0.875rem;color:#555}