.tooltip {
    position: relative;
    display: inline-block;
    border-bottom: 1px dotted black;
}

.tooltip .tooltiptext {
    visibility: hidden;
    width: 140px;
    font-size: 22px;
    color: white;
    text-align: center;
    border-radius: 6px;
    padding: 5px 0;
    bottom: 120%;
    left: 50%;
    margin-left: -70px;
    /* Use half of the width (120/2 = 60), to center the tooltip */
    /* Position the tooltip */
    position: absolute;
    z-index: 1;
}

.tooltip:hover .tooltiptext {
    visibility: visible;
}