.dropdown-submenu {
        position:relative;
    }
    .dropdown-submenu>.dropdown-menu {
        
        top:0;
        left:100%;
        margin-top:0;
        margin-left-radius:0;
    }
    .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-left-color:#cccccc;
        margin-top:5px;
        margin-right:-10px;
    }
    .dropdown-submenu>a:after {
        border-left-color:#ffffff;
    }