@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    height: auto;
    padding: 1rem 0;
  }

  .main-nav {
    margin-top: 0.5rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
}