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

.tooltip .tooltiptext {
    visibility: hidden;
    background-color: black;
    color: #fff;
    text-align: center;
    border-radius: 6px;
    padding: 5px 10px;
    /* positioning */
    position: absolute;
    z-index: 1;
    left: 200%;
    top: 100%;
    margin-left: -60px;
}

.tooltip:hover .tooltiptext {
    visibility: visible;
    animation-name: tooltipappear;
    animation-duration: 1s;
}

@keyframes tooltipappear {
    0% {
        color: rgba(255, 255, 255, 0);
         background-color: rgba(255, 255, 255, 0);
    }

    100% {
        color: rgba(255, 255, 255, 255);
    }
}