@media (max-width: 1023px) {
    .cart-header  { padding: 4rem 1.5rem 2rem !important; }
    .cart-content { padding: 2rem 1.5rem 3rem !important; }
  }
  @media (max-width: 900px) {
    .cart-grid    { grid-template-columns: 1fr !important; }
    .cart-sidebar { position: static !important; top: auto !important; }
  }
  @media (max-width: 639px) {
    .cart-header  { padding: 4rem 1rem 1.5rem !important; }
    .cart-header h1 { font-size: 1.75rem !important; }
    .cart-content { padding: 1.5rem 1rem 2.5rem !important; }
  }