/* unobtrusively style deep-linking heading anchors */
.anchor {
  color: gray;
  display: inline-block;
  margin-left: -1rem;
  opacity: 0;
  padding-right: 0.1rem;
  -webkit-transition: opacity cubic-bezier(0,1,.35,.96) 1s;
  -moz-transition: opacity cubic-bezier(0,1,.35,.96) 1s;
  -ms-transition: opacity cubic-bezier(0,1,.35,.96) 1s;
}
h2:hover .anchor,
h3:hover .anchor,
h4:hover .anchor,
h5:hover .anchor,
h6:hover .anchor {
  opacity: 1;
  text-decoration: none;
}