Multi-level menus in Bootstrap 3.2.0

HTML

<link rel="stylesheet" href="http://getbootstrap.com/dist/css/bootstrap.min.css">
<script src="http://getbootstrap.com/dist/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="http://fortawesome.github.io/Font-Awesome/assets/font-awesome/css/font-awesome.css">
 
    <div class="btn-group">
      <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">
        Action <span class="caret"></span>
    </button>
    <ul class="dropdown-menu" role="menu" aria-labelledby="dropdownMenu" >
      <li><a href="#">Action</a></li>
      <li><a href="#">Another action</a></li>
      <li><a href="#">Something else here</a></li>
      <li class="divider"></li>
      <li class="dropdown-submenu">
        <a tabindex="-1" href="#">More options</a>
        <ul class="dropdown-menu">
          <li><a tabindex="-1" href="#">Second level</a></li>
          <li class="dropdown-submenu">
            <a href="#">More..</a>
            <ul class="dropdown-menu">
                <li><a href="#">3rd level</a></li>
                <li><a href="#">3rd level</a></li>
            </ul>
        </li>
        <li><a href="#">Second level</a></li>
        <li><a href="#">Second level</a></li>
    </ul>
</li>
</ul>
</div>

CSS

.dropdown-submenu{
        position:relative;
    }
 
    .dropdown-submenu>.dropdown-menu{
        top:0;
        left:100%;
        margin-top:-6px;
        margin-left:-1px;
        -webkit-border-radius:0 6px 6px 6px;
        -moz-border-radius:0 6px 6px 6px;
        border-radius:0 6px 6px 6px;
    }
 
    .dropdown-submenu:hover>.dropdown-menu{
        display:block;
    }
 
    .dropdown-submenu>a:after{
        display:block;
        content:" ";
        float:right;
        width:0;
        height:0;
        border-color:transparent;
        border-style:solid;
        border-width:5px 0 5px 5px;
        border-left-color:#cccccc;
        margin-top:5px;
        margin-right:-10px;
    }
 
    .dropdown-submenu:hover>a:after{
        border-left-color:#ffffff;
    }
 
    .dropdown-submenu.pull-left{
        float:none;
    }
 
    .dropdown-submenu.pull-left>.dropdown-menu{
        left:-100%;
        margin-left:10px;
        -webkit-border-radius:6px 0 6px 6px;
        -moz-border-radius:6px 0 6px 6px;
        border-radius:6px 0 6px 6px;
    }