@media (max-width: 768px) {
  .nav-links ul {
    display: none;
    flex-direction: column;
    background: #111;
    padding: 15px;
    position: absolute;
    top: 60px;
    right: 0;
  }
  .nav-links.active ul { display: flex; }
  .hamburger { display: block; color: #fff; font-size: 24px; }
}