span.tool 
{
  position: relative;
}
 
span.tool span.tip 
{
  display: none;
}

span.tool:hover span.tip 
{
  display: block;
  z-index: 100;
  position: absolute;
  top: 1.6em;
  left: 0;
  width: 300px;
  padding: 3px 7px 4px 6px;
  border: 1px solid #336;
  background-color: #f7f7ee;
  font: verdana,arial,sans-serif;
  text-align: left;
  color: #000;
}

#content span.tool::after
{
  padding-left: 2px;
  content: url(/img/bubble.gif);
}