#overlay .tooltip {
    position: absolute;
    font-family: helvetica, sans-serif;
    background-color: rgba(0,0,0,0.8);
    color: white;
    padding: 2px 5px;
    font-size: 80%;
    border: 1px solid black;
    z-index: 500;
    border-radius: 2px;
    opacity: 0;
    transition: opacity 100ms;
}
