.dropdown-submenu {
  position: relative;
}

.dropdown-submenu .dropdown-menu {
  top: 0;
  left: 100%;
  margin-top: -1px;
  display: none; /* Hidden by default */
}

.dropdown-submenu:hover > .dropdown-menu,
.dropdown-submenu .dropdown-menu.show {
  display: block; /* Show on hover or if toggled */
}