#btn-group li{
    display: inline-block;
    vertical-align: middle;
    cursor: pointer;
    text-align: center;
    font-size: 18px;    
    width: 25%;
  }

  #btn-group li a {
    display: block;
    line-height: 48px;
  }

  #btn-group li a:hover {      
    color: #fff;
    background-color: #2f2f2f;
  }

  #btn-group li ul {
    display: none;
  }
  #btn-group li:hover ul{
    display: block;
    position: absolute;
  }

  #btn-group{
    display: block;
    font-size:0px;/*btn-group 否则内li有间隔，字体在li里设置*/
  }
  .dropdown-menu .divider {
      height: 1px;
      margin: 0px 0;
      overflow: hidden;
      background-color: #e5e5e5;
  }
  .dropdown-menu {
    position:absolute;
    left: 196px;
    top:108px;
    z-index: 1000;
    float: left;
    min-width: 140px;
    line-height: 35px;
    font-size: 16px;
    text-align: center;
    background-color: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-shadow: 0 6px 12px rgba(0,0,0,.175);
  }

  .dropdown-menu li{
    display: block!important;
    width: 100%!important;    
  }

  .dropdown-menu li a{
    width: 220px;
    color: #000!important;    
  }
  .dropdown-menu li a:hover {    
    background-color: #eee!important;
  }