<style>
/* Pure CSS Tooltips */
span.info{
  position:relative; /*this is the key*/
  z-index:24;
}
span.info:hover{
  z-index:25;
  background-color:#ff0
}
span.info span{
 display:none
}
span.info:hover span{ /*the span will display just on :hover state*/
   display:block;
   position:absolute;
   top:1em;
   left:1em;
   border:1px solid #ccc;
   background-color: #666;
   color:#eee;
   text-align:left;
   padding:6px;
}
</style>
