animated-dropdown.css

/* Animated dropdown menu */
.navbar {
    .dropdown-menu {
        display: block;
        visibility: hidden;
        opacity:0;
        transform: translateY(0.5rem);
        transition:.2s ease all;
    }
    .dropdown-menu.show {
        display: block;
        visibility: visible;
        opacity:1;
        transform: translateY(0px);
        transition:.2s ease all;
    }

}