Edit in JSFiddle

<div class="container">
  <div class="label">
    <span class="tooltip-toggle" data-tooltip="Sample text for your tooltip!">Hover over this
        </span>

  </div>
</div>

html,
body {
  padding: 4rem;
}

.container {
  background-color: #000;
  border-radius: 4px;
  box-shadow: 0 1px 2px 0 rgba(153, 153, 153, 0.35);
  padding: 1em;
  border: 1px solid #eee;
  display: block;
  width: 200px;
  color: #fff
}

.label {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -webkit-align-items: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
  -ms-flex-pack: center;
  justify-content: center;
}

.tooltip-toggle {
  cursor: pointer;
  position: relative;
}

.tooltip-toggle::before {
  position: absolute;
  top: -80px;
  left: -80px;
  background-color: green;
  border-radius: 5px;
  color: #fff;
  content: attr(data-tooltip);
  padding: 1rem;
  text-transform: none;
  -webkit-transition: all 0.5s ease;
  transition: all 0.5s ease;
  width: 160px;
}

.tooltip-toggle::after {
  position: absolute;
  top: -12px;
  left: 9px;
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-top: 5px solid green;
  content: " ";
  font-size: 0;
  line-height: 0;
  margin-left: -5px;
  width: 0;
}

.tooltip-toggle::before,
.tooltip-toggle::after {
  color: #efefef;
  font-family: monospace;
  font-size: 16px;
  opacity: 0;
  pointer-events: none;
  text-align: center;
}

.tooltip-toggle:hover::before,
.tooltip-toggle:hover::after {
  opacity: 1;
  -webkit-transition: all 0.75s ease;
  transition: all 0.75s ease;
}