.menu-toggle {
  display: none;
  background: none;
  border: 0;
  color: #0f172a;
  cursor: pointer;
  font-size: 24px;
}

.nav { position: relative; }

@media (max-width: 640px) {
  .nav-links { display: none !important; }
  .nav-links.mobile-open {
    display: flex !important;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 99;
    gap: 16px;
    padding: 20px;
    background: #fff;
    border-bottom: 1px solid #e2e8f0;
    box-shadow: 0 8px 16px rgba(0, 0, 0, .05);
  }
  .nav-links.mobile-open a { display: block !important; }
  .menu-toggle { display: block; }
}