a.tooltip{
    position:relative; /*this is the key*/
    z-index:24; background-color:#ccc;
    color:#000;
    text-decoration:none;
	vertical-align:bottom;
	cursor:pointer;
}

a.tooltip:hover{z-index:25; background-color:#ff0}

a.tooltip span{display: none}

a.tooltip:hover span{ /*the span will display just on :hover state*/
    display:block;
    position:absolute;
    top:2em; left:2em; 
	width:15em;
    border:1px solid #0cf;
    background-color:#cff; color:#000;
    text-align: center
}

/* 
tooltip_big für größere texte
*/
a.tooltip_big{
    position:relative; /*this is the key*/
    z-index:24; background-color:#ccc;
    color:#000;
    text-decoration:none;
	vertical-align:bottom;
	cursor:pointer;
}

a.tooltip_big:hover{z-index:25; background-color:#ff0}

a.tooltip_big span{display: none}

a.tooltip_big:hover span{ /*the span will display just on :hover state*/
    display:block;
    position:absolute;
    top:2em; left:2em; 
	width:300px;
    border:1px solid #0cf;
    background-color:#cff; color:#000;
    text-align: center
}