h1, h2, h3, h4, h5, h6 {
  position: relative;
  scroll-margin-top: 1em;
}

a.anchor {
  position: absolute;
  left: 0;
  text-decoration: none;
  transition: opacity .2s ease-out;
  opacity: 0;
}
a.anchor:after {
  content: '§';
}
a.anchor:is(:hover, :focus-within) {
  opacity: 1;
}

:is(h1, h2, h3, h4, h5, h6):is(:hover, :target) a.anchor {
  opacity: 1;
}