thsf.net/build/lib/thsf/static/css/tooltip.css

.tooltip, .planning_tooltip {
  position: relative;
  display: inline-block;
}


.tooltip .tooltiptext {
  visibility: hidden;
  background-color: var(--main-color);
  color: var(--alt-main-color);
  text-align: center;
  border-radius: 6px;
  padding: 5px 0;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  margin-left: -60px;
  opacity: 0;
  transition: opacity 1s;
}

.tooltip .tooltiptext::after, .planning_tooltip .planning_tooltiptext::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -5px;
  border-width: 5px;
}

.tooltip:hover .tooltiptext, .planning_tooltip:hover .planning_tooltiptext  {
  visibility: visible;
  opacity: 1;
  font-size: 0.7em;
  padding: 0.2em;
}

.planning_tooltip .planning_tooltiptext {
  visibility: hidden;
  background-color: var(--main-color);
  color: var(--alt-main-color);
  text-align: center;
  border-radius: 6px;
  padding: 5px 0;
  position: absolute;
  z-index: 1;
  bottom: 0;
  left: 0;
  opacity: 0;
  transform: translateX(2em) translateY(-3em);
  transition: opacity 1s;
}