element.style {
  margin-bottom: 1em;
}

/* Optional / "going deeper" callouts.
   Add the `.optional` class to a callout to mark it as skippable on a first
   pass, e.g. ::: {.callout-note .optional collapse="true"}
   The label and muted border signal that the box is not part of the main thread. */
.callout.optional {
  border-left-color: #9aa0a6;
}
.callout.optional .callout-title-container::after,
.callout.optional .callout-title::after {
  content: " · optional";
  font-style: italic;
  font-weight: normal;
  opacity: 0.7;
}

/* Optional whole sections: add the `.optional` class to the heading,
   e.g. ## Going deeper {.optional} */
section.optional > h1::after, section.optional > h2::after,
section.optional > h3::after, section.optional > h4::after,
h1.optional::after, h2.optional::after,
h3.optional::after, h4.optional::after {
  content: " · optional";
  font-style: italic;
  font-weight: normal;
  opacity: 0.7;
}

/* Timetable: span the full page width and keep every row on a single line */
.timetable table {
  width: 100%;
}

.timetable th,
.timetable td {
  white-space: nowrap;
}