.dropdown-submenu {
    position: relative;
  }
  
.dropdown-submenu .dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    border-radius: 0;
  }
  
.dropdown-submenu:hover .dropdown-menu {
    display: block;
  }
  
.dropdown-submenu:hover > a:after {
    border-left-color: #fff;
  }
  
.dropdown-submenu.pull-left {
    float: none;
  }