@media (max-width: 991px) {
    #buildpress-navbar-collapse {
        display: block;
        max-height: 0;
        overflow: hidden;
        opacity: 0;
        transition: max-height .35s ease, opacity .35s ease;
    }

    #buildpress-navbar-collapse.menu-open {
        max-height: 700px;
        opacity: 1;
    }
}