:root{font-family:system-ui,-apple-system,Segoe UI,sans-serif;line-height:1.5;color:#1a1a1a}body{margin:0;min-height:100vh;display:grid;place-items:center;background:#f5f7fa}main{text-align:center;max-width:640px;padding:2rem;background:#fff;border-radius:12px;box-shadow:0 10px 30px #00000014}pre{text-align:left;background:#0f172a;color:#7dd3fc;padding:1rem;border-radius:8px;overflow-x:auto}.error{color:tomato;font-weight:600}