main {
  min-height: calc(100vh - 14 * var(--vertical-margin));
}

footer {
  display: inherit;
  margin: calc(4 * var(--vertical-margin)) 0;
}

details {
  margin: 0 var(--horizontal-margin);
  max-width: 768px;
}

details[open] {
  margin: calc(2 * var(--vertical-margin)) var(--horizontal-margin);
}

details>summary {
  display: block;
  list-style: none;
  border: none;
  outline: none;
  cursor: pointer;
  margin-left: 1rem;
}

summary::after {
  display: block;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

details p:first-of-type {
  margin-top: var(--vertical-margin);
}

details p:last-of-type {
  margin-bottom: calc(2 * var(--vertical-margin));
}

figure {
  display: inline-block;
  margin: 0 0 var(--vertical-margin);
}

img {
  margin: 0;
  width: 3.5rem;
  height: auto;
}

/** Keroine */
li::before {
  content: '— ';
  margin-left: calc(-0.88rem - 0.25rem);
}

/** Keroine end */