body{margin:0;font-family:Arial}header{position:sticky;top:0;background:#000;color:#fff;padding:15px;display:flex;justify-content:space-between}nav a{color:#fff;margin:0 10px;text-decoration:none}.hero{padding:90px 20px;background:#222;color:#fff;text-align:center}.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:15px}.card,section,footer{padding:20px}footer{background:#111;color:#fff}