a.tooltip{
  position:relative; 
  font-size:12px; 
  color:#039;
  text-decoration:none;
  cursor:help; 
}

a.tooltip:hover{
background:transparent;
color:red;
z-index:25; 

}
a.tooltip span{display: none;
}

a.tooltip:hover span{ 
display:block;
position:absolute;
width:210px; 
top:20px;
left:0;
font-size: 12px;
padding:5px;
border:1px solid #999;
background:green; 
color:#000;
}