body {
  padding-top: 50px;
  padding-bottom: 20px;
}
  .buku{
  width: 250px;
  height:360px;
  border:1px solid #dedbd1;
}

 .clear{
              clear: both;
            }
            ul{
              
              list-style-type: none;
              padding: 0;
              margin: 0;

            }
            ul#nav {
              margin-top: 10px;

            }
           
            ul#nav li{

              background:#26A81B;float: left;color:#fff;
              
            }
            ul#nav li a{
              display: block;padding: 5px 10px;color: #fff;
              
            }

            ul#nav li a:hover{ background: rgba(0,0,0,0.3);

            }
            ul#nav li ul li{
              float: none;

            }
            ul#nav li ul{
              position: absolute;display: none;
            }
            ul#nav li:hover ul{
              display: block;
          }