body {
  height: 100vh;
  margin: 0;
  background: #333;
  display: -webkit-box;
  display: flex;
  -webkit-box-align: center;
          align-items: center;
  -webkit-box-pack: center;
          justify-content: center;
  font-family: Phosphate, sans-serif;
  color: #8c0f34;
}
.box {
  padding: 2rem;
  font-size: 4rem;
  background: -webkit-gradient(linear, left top, right top, from(#f598a8), to(#f6edb2));
  background: linear-gradient(90deg, #f598a8, #f6edb2);
  border-radius: 1rem;
}

[data-tooltip] {
  position: relative;
}
[data-tooltip]::before {
  -webkit-transition: 0.3s;
  transition: 0.3s;
  position: absolute;
  display: block;
  background: rgba(0,0,0,0.3);
  font-size: 1.25rem;
  padding: 1rem;
  color: #fff;
  content: '';
  top:-4rem;
  left: 50%;
  -webkit-transform: translate3d(-50%,100%,0);
          transform: translate3d(-50%,100%,0);
  border-radius: 0.5rem;
  content: attr(data-tooltip);
  font-family: sans-serif;
  opacity: 0;
}

[data-tooltip]:hover::before {
  -webkit-transform:translate3d(-50%,0%,0);
          transform:translate3d(-50%,0%,0);
  opacity: 1;
}