.tooltip {
  padding: 12px;
  background: rgba(0, 0, 0, 0.8);
  color: #fff;
  border-radius: 5px;
  position: absolute;
  text-align: center;
  transform: translate(-50%, -100%);
}

.tooltip.hidden {
  display: none;
}

.tooltip:after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -10px;
  border-top: 10px solid rgba(0, 0, 0, 0.8);
  border-right: 10px solid transparent;
  border-left: 10px solid transparent;
}