@media (max-width: 992px) {
    #header .navbar-toggle {
      display: block;
    }
    #main-menu-inner.collapse {
      display: none !important;
    }
    #main-menu-inner.collapsing {
      display: block;
    }
    #main-menu-inner.collapse.in {
      display: block!important;
    }
    #main-menu-inner {
      height: 100%;
      overflow-y: hidden;
    }
    #main-menu-inner ul, 
    #main-menu-inner li {
      display: block;
    }
}