.ai-hero {
  position: relative;
  overflow-x: clip;
  background:
    linear-gradient(118deg, var(--color-accent-05), var(--color-transparent)),
    var(--color-bg);
}

.ai-hero::after {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 1px;
  background: var(--color-border);
  content: "";
}

.ai-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(320px, .75fr);
  align-items: center;
  gap: 72px;
  padding-top: 72px;
  padding-bottom: 84px;
}

.ai-hero-copy h1 {
  max-width: 820px;
  margin: 20px 0 0;
}

.ai-keyword {
  text-decoration: underline;
  text-decoration-color: var(--color-clay);
  text-decoration-skip-ink: none;
  text-decoration-thickness: 3px;
  text-underline-offset: 10px;
}

.ai-hero-summary {
  max-width: 760px;
  margin: 28px 0 0;
  color: var(--color-muted);
  font-family: var(--font-serif);
  font-size: 20px;
  line-height: 1.65;
}

.ai-signal-board {
  padding: 28px;
  border-radius: var(--radius-sm);
  background: var(--color-text);
  box-shadow: var(--shadow-tint);
  color: var(--color-bg);
}

.ai-board-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--color-white-18);
  color: var(--color-paper-72);
  font-size: 11px;
  letter-spacing: .1em;
}

.ai-board-row {
  display: grid;
  grid-template-columns: minmax(90px, .55fr) minmax(0, 1.45fr);
  gap: 20px;
  padding-top: 18px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--color-white-18);
}

.ai-board-row span {
  color: var(--color-paper-58);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
}

.ai-board-row strong {
  color: var(--color-bg);
  font-size: 14px;
  font-weight: 650;
}

.ai-tool-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 22px;
}

.ai-tool-strip span {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  max-width: 100%;
  padding: 4px 10px;
  overflow: hidden;
  border: 1px solid var(--color-white-22);
  border-radius: var(--radius-pill);
  color: var(--color-paper-72);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .05em;
}

.ai-document {
  padding-top: 42px;
  padding-bottom: 104px;
}

.ai-chapter {
  padding-top: 72px;
  padding-bottom: 72px;
  border-bottom: 1px solid var(--color-border);
}

.ai-chapter:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.ai-section-heading {
  max-width: 900px;
  margin-bottom: 38px;
}

.ai-section-heading h2 {
  margin: 14px 0 16px;
}

.ai-section-heading > p:last-child {
  max-width: 760px;
  margin-bottom: 0;
  color: var(--color-muted);
  font-family: var(--font-serif);
  font-size: 18px;
}

.ai-intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, .8fr);
  gap: 64px;
  align-items: start;
}

.ai-prose {
  font-family: var(--font-serif);
  font-size: 18px;
  line-height: 1.85;
}

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

.ai-reading {
  max-width: var(--reading-width);
}

.ai-definition-list {
  margin: 0;
  background: var(--color-panel-muted);
}

.ai-definition-list div {
  padding: 20px 22px;
  border-bottom: 1px solid var(--color-border);
}

.ai-definition-list div:last-child {
  border-bottom: 0;
}

.ai-definition-list dt {
  margin-bottom: 7px;
  font-family: var(--font-display);
  font-weight: 750;
}

.ai-definition-list dd {
  margin: 0;
  color: var(--color-muted);
  font-family: var(--font-serif);
  line-height: 1.65;
}

.ai-tool-table td {
  font-family: var(--font-serif);
  line-height: 1.6;
}

.ai-tool-table td:first-child {
  font-family: var(--font-display);
}

.ai-profile-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--color-border);
}

.ai-profile {
  min-width: 0;
  padding: 34px;
  background: var(--color-panel);
}

.ai-profile:nth-child(3n) {
  background: var(--color-panel-muted);
}

.ai-profile h3 {
  margin: 22px 0 14px;
  font-size: 24px;
}

.ai-profile p {
  color: var(--color-muted);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.75;
}

.ai-profile p:last-child {
  margin-bottom: 0;
}

.ai-profile-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .12em;
}

.ai-split-notes {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.ai-note-panel {
  min-width: 0;
  padding: 38px;
  background: var(--color-panel-muted);
}

.ai-note-panel-dark {
  background: var(--color-text);
  color: var(--color-bg);
}

.ai-note-panel h3 {
  margin: 20px 0 14px;
}

.ai-note-panel-dark h3 {
  color: var(--color-bg);
}

.ai-note-panel p,
.ai-note-panel li {
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.75;
}

.ai-note-panel p {
  color: var(--color-muted);
}

.ai-note-panel-dark p,
.ai-note-panel-dark li {
  color: var(--color-paper-72);
}

.ai-note-panel ul {
  display: grid;
  gap: 9px;
  margin: 22px 0 0;
  padding-left: 20px;
}

.ai-note-label {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 750;
  letter-spacing: .14em;
}

.ai-note-panel-dark .ai-note-label {
  color: var(--color-clay);
}

.ai-workflow {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 48px;
}

.ai-workflow article {
  min-width: 0;
  padding: 28px;
  border-top: 4px solid var(--color-accent);
  background: var(--color-panel-muted);
}

.ai-workflow article:nth-child(2) {
  border-top-color: var(--color-moss);
}

.ai-workflow article:nth-child(3) {
  border-top-color: var(--color-slate);
}

.ai-workflow .mono {
  color: var(--color-muted);
  font-size: 11px;
  letter-spacing: .12em;
}

.ai-workflow h3 {
  margin: 22px 0 12px;
}

.ai-workflow p {
  margin-bottom: 0;
  color: var(--color-muted);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.75;
}

.ai-failure-list {
  max-width: 980px;
}

.ai-conclusion-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(300px, .65fr);
  gap: 64px;
  align-items: start;
}

.ai-route-card {
  position: sticky;
  top: var(--toc-offset);
  padding: 30px;
  border-radius: var(--radius-sm);
  background: var(--color-panel-muted);
}

.ai-route-card .mono {
  color: var(--color-accent);
  font-size: 11px;
  letter-spacing: .12em;
}

.ai-route-card h3 {
  margin: 20px 0 12px;
}

.ai-route-card p {
  color: var(--color-muted);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.7;
}

.ai-route-card .btn-row {
  margin-top: 24px;
}

@media (max-width: 1024px) {
  .ai-hero-grid {
    grid-template-columns: minmax(0, 1fr) minmax(300px, .75fr);
    gap: 38px;
  }

  .ai-intro-grid,
  .ai-conclusion-grid {
    gap: 38px;
  }

  .ai-workflow {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .ai-hero-grid,
  .ai-intro-grid,
  .ai-conclusion-grid {
    grid-template-columns: 1fr;
  }

  .ai-hero-grid {
    gap: 36px;
    padding-top: 42px;
    padding-bottom: 56px;
  }

  .ai-hero-summary {
    font-size: 18px;
  }

  .ai-document {
    padding-top: 30px;
    padding-bottom: 68px;
  }

  .ai-chapter {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .ai-profile-grid,
  .ai-split-notes {
    grid-template-columns: 1fr;
  }

  .ai-profile:nth-child(3n) {
    background: var(--color-panel);
  }

  .ai-profile:nth-child(even) {
    background: var(--color-panel-muted);
  }

  .ai-route-card {
    position: static;
  }
}

@media (max-width: 640px) {
  .ai-signal-board,
  .ai-profile,
  .ai-note-panel,
  .ai-workflow article,
  .ai-route-card {
    padding: 22px;
  }

  .ai-board-row {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .ai-profile h3 {
    font-size: 22px;
  }

  .ai-prose,
  .ai-section-heading > p:last-child {
    font-size: 17px;
  }
}