svg {
  display: block;
  margin: auto;
  border: 1px solid lightgrey;
}

div.tooltip {
  position: absolute;
  text-align: center;
  padding: 7px;
  font: 12px sans-serif;
  background: lightsteelblue;
  border-radius: 4px;
  pointer-events: none;
}

.head-text {
  text-anchor: middle;
  font: 14px sans-serif;
  font-weight: bold;
}

text {
  font: 12px sans-serif;
}