.handbook-intro {
  padding-bottom: 34px;
}

.handbook-heading {
  max-width: 900px;
}

.handbook-heading .lead {
  margin-top: 22px;
}

.handbook-context {
  max-width: 900px;
  display: grid;
  gap: 16px;
  margin-top: 34px;
  color: var(--color-text-soft);
  font-size: 16px;
}

.handbook-context a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-color: var(--color-accent-deep);
  text-underline-offset: 3px;
}

.handbook-toc {
  margin-top: 40px;
}

.handbook-body {
  padding-top: 34px;
}

.handbook-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: clamp(36px, 6vw, 76px);
  align-items: start;
}

.handbook-prose {
  min-width: 0;
}

.handbook-chapter {
  scroll-margin-top: calc(var(--header-height) + 24px);
}

.handbook-chapter + .handbook-chapter {
  margin-top: clamp(92px, 11vw, 138px);
}

.handbook-chapter > h2 {
  margin-top: 0;
  margin-bottom: 32px;
}

.handbook-chapter > h3 {
  margin-top: 42px;
  margin-bottom: 14px;
}

.handbook-chapter > p + p {
  margin-top: 18px;
}

.handbook-chapter > p,
.handbook-chapter > ul,
.handbook-chapter > ol {
  color: var(--color-text-soft);
}

.handbook-chapter > .callout,
.handbook-chapter > pre,
.handbook-chapter > .data-table {
  margin-top: 28px;
  margin-bottom: 28px;
}

.chapter-index {
  margin-bottom: 13px;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.handbook-rail {
  position: sticky;
  top: 24px;
  display: grid;
  gap: 14px;
}

.handbook-rail-card {
  padding: 20px;
}

.handbook-rail-card h2 {
  margin-bottom: 15px;
  font-size: 16px;
  font-weight: 500;
}

.handbook-rail-card ol {
  display: grid;
  gap: 10px;
  padding-left: 20px;
  color: var(--color-text-muted);
  font-size: 13px;
}

.handbook-rail-card ul {
  display: grid;
  gap: 8px;
  padding: 0;
  list-style: none;
}

.handbook-rail-card a {
  display: flex;
  min-height: 38px;
  align-items: center;
  padding: 7px 10px;
  border-radius: var(--radius-small);
  color: var(--color-text-muted);
  font-size: 13px;
  transition: color var(--ease-standard), background-color var(--ease-standard);
}

.handbook-rail-card a:hover {
  background: var(--color-panel-raised);
  color: var(--color-text);
}

@media (max-width: 980px) {
  .handbook-layout {
    grid-template-columns: minmax(0, 1fr);
  }

  .handbook-rail {
    position: static;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    grid-row: 1;
  }
}

@media (max-width: 640px) {
  .handbook-intro {
    padding-bottom: 24px;
  }

  .handbook-body {
    padding-top: 24px;
  }

  .handbook-context {
    font-size: 15px;
  }

  .handbook-rail {
    grid-template-columns: 1fr;
  }

  .handbook-chapter + .handbook-chapter {
    margin-top: 88px;
  }

  .handbook-chapter > h2 {
    margin-bottom: 26px;
  }

  .handbook-chapter > h3 {
    margin-top: 36px;
  }
}