a.tooltip b {display:none;}
a.tooltip:hover {border:0; position:relative; z-index:500; text-decoration:none;}
a.tooltip:hover b {display:block; position:absolute; top:20px; left:-25px; padding:5px; font-weight:normal; color:#000; border:1px solid #888; background:#eee; padding:3px; width:300px; text-align:justify}
a.tooltip:hover b em {position:absolute; left:20px; top:-6px; width:11px; height:6px; 
background: url(../interfaz/tooltip.gif); 
display:block; 
font-size:1px;}