.dropdown-submenu {
  position: relative;
}

.dropdown-submenu > .dropdown-menu {
  top: 0;
  left: 100%;
  margin-left: 0.1rem;
  margin-right: 0.1rem;
  display: none;
  position: absolute;
}

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