[data-title]:hover:after { 
    visibility: visible; 
} 
  
[data-title]:after { 
    content: attr(data-title); 
    background-color: #000000b8;     
    font-size: 80%;
    color: #ffffff; 
    position: absolute; 
    padding: 4px 8px 4px 8px; 
    visibility: hidden; 
    z-index: 10;
}