iot-web-ui/src/app/modules/overview/camera-stream/camera-stream.component.scss

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

.tooltip .tooltiptext {
  visibility: hidden;
  width: 300px;
  padding: 10px;
  background-color: #fff;
  color: black;
  border-radius: 6px;
  position: absolute;
  z-index: 1;
  bottom: 100%;
  left: 50%;
  margin-left: -60px;
}

.tooltip:hover .tooltiptext {
  visibility: visible;
}