:root{font-family:system-ui,-apple-system,Segoe UI,Arial,sans-serif;line-height:1.5;color-scheme:light dark}body{margin:0;min-height:100vh;background:#f7f7f8;color:#1a1a1a}.app{max-width:720px;margin:0 auto;padding:2rem 1.5rem}h1{margin-top:0}pre{background:#1a1a1a;color:#f5f5f5;padding:.75rem 1rem;border-radius:6px;overflow-x:auto}pre.error{background:#fee;color:#900}