@media (max-width: 768px) {
  .category-nav {
    top: 0 !important;
    right: 0 !important;
    bottom: 60px !important;
    left: 0 !important;
    z-index: 163999 !important;
  }
}

@media (min-width: 480px) and (max-width: 767px),
       (orientation: landscape) and (max-height: 500px) {
  .category-nav {
    top: 54px !important;
    bottom: 0 !important;
  }
}