CSS hover Box

Hi

Popupbox over a link. This is very cool and you can get creative! I am not going to explain the code below but feel free to ask questions.

Code:

css:
/*************tooltip***************************/
.tooltip {
cursor: hand;
text-decoration: none !important;
position: relative;
}
.tooltip span {
margin-left: -999em;
position: absolute;
color: #000000;
}
.tooltip:hover span {
border-radius: 5px 5px;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
box-shadow: 5px 5px 5px rgba(0, 0, 0, 0.1);
-webkit-box-shadow: 5px 5px rgba(0, 0, 0, 0.1); //browser
-moz-box-shadow: 5px 5px rgba(0, 0, 0, 0.1); //browser
font-family: arial,Geneva, sans-serif;
position: absolute;
left: 1em;
top: 2em;
z-index: 99;
margin-left: 0;
width: 250px;
}
.tooltip:hover em {
font-family: arial, Geneva, sans-serif;
font-size: 1.2em;
font-weight: bold;
display: block;
padding: 0.2em 0 0.6em 0;
}

.info {
background: #FFFFFF;
border: 1px solid #000000;
}

html a:hover {
background: transparent;
}

html:
<div id='ID'><a class="tooltip" href="http://LINK"><span class="CUSTOMINFO"><em>HEADING</em>INFO</span></a> </div>