.hover{
    text-decoration: underline;
    border-bottom: 1px solid;
}
.hover:hover{
    text-decoration: none;
    border-bottom: none;
}
.hover span{    
    visibility: hidden;
    position: absolute;
    opacity: 0;
    transition: opacity 500ms;
}
.hover:hover span{
    visibility: visible;
    position: absolute;
    display: inline;
    opacity: 1;
    color: #333;
    font-size: 80%;
    margin: 15px -20px;
    height: auto;
    background: #F9F9F9;
    border: 1px solid #CCC;
    width: 300px;
    padding: 1em;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(100,100,100,0.3);
}
.hover:hover span span{
    position: relative;
    margin: auto;
    height: auto;
    width: auto;
    border: none;
    padding: 0;
}