a.go-to-source::before {
  transition: color   0.25s, opacity 0.25s;
  color: rgba(0, 0, 0, 0.07);
  content: "📄";
}
a.go-to-source {
  position: absolute;
  top: 0.6rem;
  right: 4.0rem;
  width: 2.8rem;
  height: 2.8rem;
  border-radius: 0.2rem;
  font-size: 1.6rem;
  cursor: pointer;
  z-index: 1;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
}
pre:hover .go-to-source::before,
.codehilite:hover .go-to-source::before, .md-typeset .highlight:hover .go-to-source::before {
  color: rgba(0, 0, 0, 0.54);
}
.go-to-source:focus::before, .go-to-source:hover::before {
  color: #536dfe;
}
button.snippet-button.copy-snippet,
a.snippet-button.go-to-source > span.pln {
  visibility: collapse;
}