*{box-sizing:border-box}body{margin:0;font-family:Arial,sans-serif;background:#fafafa;color:#111}.topbar{background:#111827;padding:14px 20px}.brand{color:#fff;text-decoration:none;font-weight:700}.container{max-width:1024px;margin:0 auto;padding:20px}.grid{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(240px,1fr))}.card{background:#fff;border:1px solid #ddd;border-radius:8px;padding:12px}.error{color:#b91c1c}