body{font-family:Arial;margin:0}header{background:#2e7d32;padding:15px}nav a{color:#fff;margin-right:15px;text-decoration:none}.container{padding:20px}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:20px}.card{border:1px solid #ddd;padding:15px}