#tooltip
{
    text-align: center;
    color: #fff;
    background: #111;
    position: absolute;
    z-index: 100;
    padding: 15px;
}
 
#tooltip:after /* triangle decoration */
{
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 10px solid #111;
    content: '';
    position: absolute;
    left: 50%;
    bottom: -10px;
    margin-left: -10px;
}

    #tooltip.top:after
    {
        border-top-color: transparent;
        border-bottom: 10px solid #111;
        top: -20px;
        bottom: auto;
    }

    #tooltip.left:after
    {
        left: 10px;
        margin: 0;
    }

    #tooltip.right:after
    {
        right: 10px;
        left: auto;
        margin: 0;
    }