.sidebar-nav {
    padding: 9px 0;
}

 .dropdown-menu .sub-menu {
            left: 100%;
            position: absolute;
            top: 0;
            visibility: hidden;
            margin-top: -1px;
        }

        .dropdown-menu li:hover .sub-menu {
            visibility: visible;
        }

        .dropdown:hover .dropdown-menu {
            display: block;
        }

        .nav-tabs .dropdown-menu, .nav-pills .dropdown-menu, .navbar .dropdown-menu {
            margin-top: 0;
        }

        .navbar .sub-menu:before {
            border-bottom: 7px solid transparent;
            border-left: none;
            border-right: 7px solid rgba(0, 0, 0, 0.2);
            border-top: 7px solid transparent;
            left: -7px;
            top: 10px;
        }

        .navbar .sub-menu:after {
            border-top: 6px solid transparent;
            border-left: none;
            border-right: 6px solid #fff;
            border-bottom: 6px solid transparent;
            left: 10px;
            top: 11px;
            left: -6px;
        }