.dropdown-submenu {
    position: relative;
}

.dropdown-submenu .dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -1px;
    display: none;
}

.dropdown-submenu:hover > .dropdown-menu {
    display: block;
}

/* Ensure submenu opens on click for mobile or touch devices */
@media (max-width: 991.98px) {
    .dropdown-submenu .dropdown-menu {
        position: static;
        margin: 0;
        border: 0;
        box-shadow: none;
    }
}