.dropdown-submenu{
    position: relative;
}
.dropdown-submenu a::after{
    transform: rotate(-90deg);
    position: absolute;
    right: 3px;
    top: 40%;
}
.dropdown-submenu:hover .dropdown-menu, .dropdown-submenu:focus .dropdown-menu{
    display: flex;
    flex-direction: column;
    position: absolute !important;
    margin-top: -30px;
    left: 100%;
}
@media (max-width: 992px) {
    .dropdown-menu{
        width: 50%;
    }
    .dropdown-menu .dropdown-submenu{
        width: auto;
    }
}