en.javascript.info/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/2-hoverintent/source.view/style.css

.hours {
  color: red;
}

.minutes {
  color: green;
}

.seconds {
  color: blue;
}

.clock {
  border: 1px dashed black;
  padding: 5px;
  display: inline-block;
  background: yellow;
  position: absolute;
  left: 0;
  top: 0;
}

.tooltip {
  position: absolute;
  background: #eee;
  border: 1px brown solid;
  padding: 3px;
}