@media (max-width: 767px) 
  {
    .main-menu nav ul li.dropdown-holder ul li.dropdown-holder .fa {
    display: block;
  }

  .main-menu .navbar-nav>li.dropdown-holder>.sub-menu>li.dropdown-holder .sub-menu {
    display: none;
    width: 100%;
    position: static;
    opacity: 1;
    visibility: visible;
    -webkit-transition: none;
    -moz-transition: none;
    -ms-transition: none;
    -o-transition: none;
    transition: none;
    -webkit-transform: scaleY(1);
    -moz-transform: scaleY(1);
    -ms-transform: scaleY(1);
    -o-transform: scaleY(1);
    transform: scaleY(1);
  }
  }