.tooltip {
  position: absolute;
  z-index: 1;
  padding: 5px;
  background: rgba(0, 0, 0, 0.3);
  opacity: 1;
  border-radius: 3px;
  text-align: center;
  pointer-events: none;
  color: white;
  transition: opacity .1s ease-out;
}

.tooltip.tooltip-hidden {
  opacity: 0;
}