.dropdown-menu li {
  position: relative;
}

.dropdown-menu .dropdown-submenu {
  display: none;
  position: absolute;
  left: 100%;
  top: -7px;
}

.dropdown-menu .dropdown-submenu-left {
  right: 100%;
  left: auto;
}

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