.doc-hero {
  padding-top: var(--space-8);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border);
  background:
    linear-gradient(var(--color-grid) 1px, var(--color-transparent) 1px),
    linear-gradient(90deg, var(--color-grid) 1px, var(--color-transparent) 1px),
    var(--color-bg);
  background-size: 48px 48px;
}

.doc-hero h1 {
  max-width: 880px;
}

.doc-lead {
  max-width: 820px;
  margin-bottom: var(--space-7);
  color: var(--color-text-muted);
  font-size: clamp(18px, 2vw, 22px);
  line-height: 1.65;
}

.doc-intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(250px, 0.55fr);
  gap: var(--space-5);
  align-items: stretch;
}

.doc-intro-grid .panel {
  background: var(--color-bg);
}

.doc-intro-grid .panel p:last-child {
  margin-bottom: 0;
}

.doc-intro-grid a {
  color: var(--color-accent-dark);
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.doc-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--color-border-strong);
  border-left: 1px solid var(--color-border-strong);
  background: var(--color-bg);
}

.doc-facts span {
  display: flex;
  min-height: 72px;
  align-items: center;
  padding: var(--space-4);
  border-right: 1px solid var(--color-border-strong);
  border-bottom: 1px solid var(--color-border-strong);
  color: var(--color-text);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  overflow-wrap: anywhere;
}

.doc-toc-wrap {
  position: relative;
  z-index: 20;
  padding-top: var(--space-6);
  padding-bottom: var(--space-6);
}

.doc-toc-wrap .jump-toc {
  top: var(--space-2);
}

.doc-prose {
  color: var(--color-text-muted);
}

.doc-chapter {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: var(--space-6);
  padding-top: var(--section-space);
  padding-bottom: var(--section-space);
  border-top: 1px solid var(--color-border);
  scroll-margin-top: calc(var(--header-height) + var(--space-7));
}

.doc-chapter:first-child {
  border-top-color: var(--color-border-strong);
}

.chapter-index {
  position: sticky;
  top: calc(var(--header-height) + var(--space-5));
  align-self: start;
  padding-top: var(--space-2);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.12em;
}

.chapter-body {
  min-width: 0;
}

.chapter-body > h2 {
  margin-top: 0;
  max-width: 860px;
}

.chapter-body > h3 {
  margin-top: var(--space-8);
}

.chapter-body > p {
  max-width: 880px;
}

.chapter-body > .callout,
.chapter-body > .data-table-wrap,
.chapter-body > pre {
  margin-top: var(--space-6);
  margin-bottom: var(--space-6);
}

.chapter-body table {
  min-width: 720px;
}

.chapter-body caption {
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-size: 12px;
}

.chapter-body pre {
  border-left: 3px solid var(--color-accent);
}

.doc-closing {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-7);
}

.doc-closing h2 {
  margin-bottom: var(--space-3);
}

.doc-closing p:last-child {
  margin-bottom: 0;
}

@media (max-width: 900px) {
  .doc-intro-grid,
  .doc-closing {
    grid-template-columns: minmax(0, 1fr);
  }

  .doc-closing .button-row {
    justify-content: flex-start;
  }
}

@media (max-width: 768px) {
  .doc-hero {
    padding-top: var(--space-7);
    padding-bottom: var(--space-7);
    background-size: 32px 32px;
  }

  .doc-lead {
    font-size: 18px;
  }

  .doc-chapter {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-3);
  }

  .chapter-index {
    position: static;
    padding-top: 0;
  }

  .chapter-body > h3 {
    margin-top: var(--space-7);
  }
}

@media (max-width: 640px) {
  .doc-facts {
    grid-template-columns: minmax(0, 1fr);
  }

  .doc-facts span {
    min-height: 54px;
  }

  .doc-toc-wrap {
    padding-top: var(--space-5);
    padding-bottom: var(--space-5);
  }

  .doc-chapter {
    padding-top: var(--section-space);
    padding-bottom: var(--section-space);
  }

  .chapter-body table {
    min-width: 640px;
  }

  .doc-closing .button-row {
    width: 100%;
  }
}