ul.menu_slider                  {   float: left; width: 170px; margin-left: 0px; clear: both; line-height:20px;}
#contenidos                     {   margin-left: 190px; width:600px; }
.demo .menu_slider a.aqui       {   color: black;}
a.boton_demo                    {   position: absolute; bottom: 0px; left: 0px;}