path.link {
  fill: none;
  stroke: #666;
  stroke-width: 1.5px;
}

path.link.twofive {
  opacity: 0.25;
}

path.link.fivezero {
  opacity: 0.50;
}

path.link.sevenfive {
  opacity: 0.75;
}

path.link.onezerozero {
  opacity: 1.0;
}

circle {
  fill: #ccc;
  stroke: #fff;
  stroke-width: 1.5px;
}

text {
  fill: -webkit-link;
  text-decoration: underline;
  font: 10px sans-serif;
  pointer-events: all;
  cursor: pointer;
}