main {
  max-width: 80ch;
  margin: auto;
}

pre {
  margin: auto;
  background: lightgray;
  padding: 1em;
  white-space: pre-wrap;
  word-break: keep-all; /* doesn't always work, see: https://github.com/w3c/csswg-drafts/issues/3434 */
}

.frag {
  opacity: 0.1;
}

.frag:hover {
  opacity: 1;
}