.deepdoc-hero {
  position: relative;
  overflow: clip;
  padding-top: clamp(64px, 9vw, 112px);
  padding-bottom: clamp(48px, 7vw, 84px);
  border-bottom: 1px solid var(--color-line);
}

.deepdoc-hero::before {
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(var(--hero-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--hero-grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(to bottom, var(--color-ink), var(--hero-grid-fade));
  content: "";
}

.deepdoc-hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.55fr);
  align-items: end;
  gap: clamp(36px, 7vw, 88px);
}

.deepdoc-hero h1 {
  max-width: 760px;
  margin-top: 20px;
  margin-bottom: 22px;
}

.deepdoc-hero .lead {
  margin-bottom: 26px;
}

.deepdoc-meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.deepdoc-index-card {
  padding: 26px;
}

.deepdoc-index-card h2 {
  margin-bottom: 14px;
  font-size: 22px;
}

.deepdoc-index-card p {
  margin-bottom: 18px;
  color: var(--color-muted);
  font-size: 14px;
}

.deepdoc-index-list {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.deepdoc-index-list li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--color-line);
  color: var(--color-muted);
  font-size: 14px;
}

.deepdoc-index-list span {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 11px;
}

.deepdoc-shell {
  display: grid;
  grid-template-columns: minmax(210px, 270px) minmax(0, 1fr);
  align-items: start;
  gap: clamp(32px, 6vw, 72px);
}

.deepdoc-nav {
  position: sticky;
  top: var(--toc-offset);
}

.deepdoc-nav .toc-tabs {
  display: grid;
  gap: 4px;
  overflow: visible;
}

.deepdoc-nav .toc-tabs a {
  width: 100%;
  white-space: normal;
}

.deepdoc-nav-note {
  margin-top: 16px;
  padding: 16px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  background: var(--color-panel);
  color: var(--color-muted);
  font-size: 13px;
}

.deepdoc-nav-note strong {
  display: block;
  margin-bottom: 5px;
  color: var(--color-ink);
}

.deepdoc-prose {
  width: 100%;
  max-width: var(--reading-width);
}

.deepdoc-prose > section {
  padding-top: 18px;
  padding-bottom: clamp(72px, 9vw, 112px);
  border-bottom: 1px solid var(--color-line);
}

.deepdoc-prose > section:first-child {
  padding-top: 0;
}

.deepdoc-prose > section:last-child {
  border-bottom: 0;
}

.deepdoc-prose h2 {
  margin-bottom: 26px;
}

.deepdoc-prose h3 {
  margin-top: 42px;
  margin-bottom: 14px;
}

.deepdoc-prose p,
.deepdoc-prose li {
  color: var(--color-muted);
}

.deepdoc-prose strong {
  color: var(--color-ink);
}

.deepdoc-prose a:not(.btn-primary):not(.btn-secondary) {
  color: var(--color-accent);
  font-weight: 700;
  text-decoration: underline;
  text-decoration-color: var(--color-line);
  text-underline-offset: 4px;
}

.deepdoc-prose a:not(.btn-primary):not(.btn-secondary):hover {
  color: var(--color-accent-deep);
  text-decoration-color: var(--color-accent);
}

.deepdoc-prose ul,
.deepdoc-prose ol {
  display: grid;
  gap: 10px;
  margin-bottom: 26px;
}

.chapter-label {
  display: inline-block;
  margin-bottom: 12px;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 750;
  letter-spacing: 0.1em;
}

.deepdoc-prose .callout {
  margin: 30px 0;
}

.deepdoc-prose .callout p:last-child {
  margin-bottom: 0;
}

.deepdoc-prose .table-scroll {
  margin: 28px 0 34px;
}

.deepdoc-prose table {
  font-size: 14px;
}

.deepdoc-prose td {
  color: var(--color-muted);
}

.deepdoc-prose pre {
  margin: 28px 0 34px;
}

.decision-chain {
  display: grid;
  gap: 12px;
  margin: 28px 0 34px;
  padding: 0;
  counter-reset: decision;
  list-style: none;
}

.decision-chain li {
  position: relative;
  min-height: 54px;
  padding: 14px 16px 14px 54px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  background: var(--color-panel);
  counter-increment: decision;
}

.decision-chain li::before {
  position: absolute;
  top: 13px;
  left: 14px;
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
  color: var(--color-canvas);
  content: counter(decision);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 750;
}

.term-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin: 28px 0 34px;
}

.term-item {
  padding: 20px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  background: var(--color-canvas);
  box-shadow: var(--shadow-panel);
}

.term-item dt {
  margin-bottom: 7px;
  color: var(--color-ink);
  font-weight: 800;
}

.term-item dd {
  margin: 0;
  color: var(--color-muted);
  font-size: 14px;
}

.deepdoc-ending {
  margin-top: 24px;
}

.deepdoc-ending .promo-block {
  max-width: var(--reading-width);
  margin-left: auto;
}

@media (max-width: 960px) {
  .deepdoc-hero-inner {
    grid-template-columns: minmax(0, 1fr);
  }

  .deepdoc-index-card {
    max-width: 680px;
  }

  .deepdoc-shell {
    grid-template-columns: minmax(0, 1fr);
  }

  .deepdoc-nav {
    position: static;
  }

  .deepdoc-nav .toc-tabs {
    display: flex;
    overflow-x: auto;
  }

  .deepdoc-nav .toc-tabs a {
    width: auto;
    white-space: nowrap;
  }

  .deepdoc-nav-note {
    display: none;
  }

  .deepdoc-prose {
    max-width: var(--reading-width);
    margin-inline: auto;
  }
}

@media (max-width: 640px) {
  .deepdoc-hero {
    padding-top: 52px;
    padding-bottom: 44px;
  }

  .deepdoc-index-card {
    padding: 20px;
  }

  .term-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .deepdoc-prose > section {
    padding-bottom: 68px;
  }

  .deepdoc-prose h3 {
    margin-top: 34px;
  }

  .deepdoc-prose .table-scroll {
    margin-top: 22px;
    margin-bottom: 28px;
  }

  .deepdoc-ending .promo-block {
    margin-left: 0;
  }
}