.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;
    background-color: #00008b;
    border: 2px solid white;
}