.dropdown-submenu{
    position:relative;
}

/* 右侧弹出菜单 */

.special-track-menu{

    display:none;

    position:absolute;

    left:100%;
    top:0;

    min-width:350px;

    background:#fff;

    border:1px solid #ddd;

    box-shadow:0 4px 10px rgba(0,0,0,.15);

    z-index:99999;
}

/* 鼠标移上去显示 */

.dropdown-submenu:hover .special-track-menu{
    display:block;
}

/* Track条目 */

.special-track-menu .dropdown-item{
    display:block;
    padding:12px 20px;
    white-space:normal;
}

/* hover效果 */

.special-track-menu .dropdown-item:hover{
    background:#f5f5f5;
}

/* Special Tracks右箭头 */

.special-track{
    position:relative;
}

.special-track::after{
    content:"›";
    position:absolute;
    right:15px;
    font-size:20px;
    color:#999;
}