:root {
  --ai-surface: var(--color-panel);
  --ai-surface-strong: var(--color-panel-strong);
  --ai-line: var(--color-border);
  --ai-line-strong: var(--color-divider);
  --ai-active: var(--color-accent);
  --ai-active-soft: var(--color-accent-soft);
  --ai-ink: var(--color-text);
  --ai-muted: var(--color-text-muted);
  --ai-information: var(--color-info);
  --ai-card-radius: var(--radius-md);
  --ai-control-radius: var(--radius-sm);
  --ai-small-radius: var(--radius-xs);
}

.ai-hero {
  overflow-x: clip;
  border-bottom: 1px solid var(--ai-line);
  padding-top: clamp(54px, 8vw, 104px);
  padding-bottom: clamp(54px, 8vw, 104px);
}

.ai-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(440px, 1.08fr);
  align-items: center;
  gap: clamp(42px, 7vw, 92px);
}

.ai-hero-copy h1 {
  max-width: 680px;
  margin-top: 20px;
  margin-bottom: 22px;
}

.ai-hero-copy h1 .no-break {
  display: block;
}

.ai-hero-copy .lead {
  max-width: 640px;
  margin-bottom: 26px;
}

.ai-hero-copy .button-row {
  margin-bottom: 22px;
}

.ai-route-panel {
  position: relative;
  border: 1px solid var(--ai-line);
  border-radius: var(--ai-card-radius);
  padding: clamp(20px, 3vw, 32px);
  background: var(--color-canvas);
  box-shadow: var(--shadow-card);
}

.ai-route-panel::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 43px;
  width: 1px;
  background: var(--ai-line);
  content: "";
}

.ai-route-head {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 30px;
  border-bottom: 1px solid var(--ai-line);
  padding-bottom: 17px;
  background: var(--color-canvas);
}

.ai-route-head > .mono {
  color: var(--ai-muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.ai-route-stage {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 130px minmax(0, 1fr);
  align-items: start;
  gap: 18px;
}

.ai-stage-label {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 8px;
  background: var(--color-canvas);
  color: var(--ai-ink);
  font-weight: 750;
}

.ai-stage-dot {
  width: 13px;
  height: 13px;
  flex: 0 0 13px;
  border: 3px solid var(--color-canvas);
  border-radius: var(--radius-pill);
  background: var(--ai-active);
  box-shadow: 0 0 0 1px var(--ai-active);
}

.ai-stage-items {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.ai-stage-items span {
  min-width: 0;
  border: 1px solid var(--ai-line);
  border-radius: var(--ai-small-radius);
  padding: 9px 10px;
  background: var(--ai-surface);
  color: var(--ai-muted);
  font-size: 0.78rem;
  text-align: center;
}

.ai-route-connector {
  width: 1px;
  height: 26px;
  margin-left: 19px;
  background: var(--ai-active);
}

.ai-route-note {
  position: relative;
  z-index: 1;
  margin-top: 28px;
  margin-bottom: 0;
  border-top: 1px solid var(--ai-line);
  padding-top: 17px;
  background: var(--color-canvas);
  color: var(--ai-muted);
  font-size: 0.82rem;
}

.ai-toc-wrap {
  position: relative;
  z-index: 20;
  padding-top: 20px;
}

.ai-section-grid {
  display: grid;
  grid-template-columns: minmax(240px, 0.72fr) minmax(0, 1.45fr);
  align-items: start;
  gap: clamp(36px, 7vw, 96px);
}

.ai-section-heading {
  min-width: 0;
}

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

.ai-section-heading > p:last-child {
  max-width: 620px;
  color: var(--ai-muted);
}

.ai-heading-wide {
  margin-bottom: 34px;
}

.ai-heading-wide h2 {
  max-width: 820px;
}

.ai-reading {
  min-width: 0;
  color: var(--ai-ink);
  line-height: 1.85;
}

.ai-reading h3 {
  margin-top: 34px;
  margin-bottom: 10px;
  font-size: clamp(20px, 2.2vw, 25px);
}

.ai-reading > h3:first-child {
  margin-top: 0;
}

.ai-reading p {
  margin-bottom: 20px;
}

.ai-reading .callout {
  margin-top: 30px;
}

.panel-section {
  border-top: 1px solid var(--ai-line);
  border-bottom: 1px solid var(--ai-line);
  background: var(--ai-surface);
}

.ai-tool-list {
  border-top: 1px solid var(--ai-line-strong);
}

.ai-tool-row {
  display: grid;
  grid-template-columns: minmax(220px, 0.65fr) minmax(0, 1.35fr);
  gap: 32px;
  border-bottom: 1px solid var(--ai-line);
  padding-top: 25px;
  padding-bottom: 25px;
}

.ai-tool-name {
  display: flex;
  align-items: flex-start;
  gap: 15px;
}

.ai-tool-mark {
  display: inline-flex;
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--ai-line-strong);
  border-radius: var(--ai-control-radius);
  background: var(--color-canvas);
  color: var(--ai-ink);
  font-family: var(--font-mono);
  font-weight: 800;
}

.ai-tool-name h3 {
  margin-bottom: 4px;
  font-size: 1.15rem;
}

.ai-tool-name p {
  margin-bottom: 0;
  color: var(--ai-muted);
  font-size: 0.68rem;
}

.ai-tool-copy p {
  margin-bottom: 0;
  color: var(--ai-muted);
}

.compare-table td {
  color: var(--ai-muted);
  line-height: 1.62;
}

.compare-table td:first-child {
  color: var(--ai-ink);
}

.ai-dev-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--ai-line);
  border-left: 1px solid var(--ai-line);
}

.ai-dev-card {
  min-width: 0;
  border-right: 1px solid var(--ai-line);
  border-bottom: 1px solid var(--ai-line);
  padding: clamp(22px, 4vw, 36px);
  background: var(--color-canvas);
}

.ai-dev-card > .mono {
  color: var(--ai-information);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.07em;
}

.ai-dev-card h3 {
  margin-top: 14px;
  margin-bottom: 10px;
  font-size: 1.3rem;
}

.ai-dev-card p {
  margin-bottom: 0;
  color: var(--ai-muted);
}

.ai-dev-callout {
  margin-top: 28px;
}

.ai-choice-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, auto);
  align-items: center;
  gap: clamp(36px, 7vw, 90px);
  border: 1px solid var(--ai-line);
  border-radius: var(--ai-card-radius);
  padding: clamp(28px, 5vw, 56px);
  background: var(--ai-surface);
  box-shadow: 0 1px 2px var(--color-shadow-soft);
}

.ai-choice-copy h2 {
  max-width: 760px;
  margin-bottom: 18px;
}

.ai-choice-copy p {
  max-width: 820px;
  color: var(--ai-muted);
}

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

.ai-choice-actions {
  display: grid;
  min-width: 210px;
  gap: 11px;
}

.ai-choice-actions .btn-primary,
.ai-choice-actions .btn-secondary {
  width: 100%;
}

.ai-choice-actions .text-link {
  padding-top: 5px;
  text-align: center;
}

@media (max-width: 980px) {
  .ai-hero-grid,
  .ai-section-grid {
    grid-template-columns: 1fr;
  }

  .ai-hero-grid {
    gap: 48px;
  }

  .ai-route-panel {
    max-width: 720px;
  }

  .ai-section-grid {
    gap: 28px;
  }

  .ai-section-heading {
    max-width: 760px;
  }
}

@media (max-width: 760px) {
  .ai-tool-row {
    grid-template-columns: 1fr;
    gap: 15px;
  }

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

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

  .ai-choice-actions {
    width: 100%;
    min-width: 0;
  }
}

@media (max-width: 640px) {
  .ai-hero {
    padding-top: 42px;
    padding-bottom: 50px;
  }

  .ai-hero-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .ai-route-panel {
    padding: 16px;
  }

  .ai-route-panel::before {
    left: 22px;
  }

  .ai-route-head {
    align-items: flex-start;
    flex-direction: column;
  }

  .ai-route-stage {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .ai-stage-label {
    gap: 10px;
    padding-top: 0;
  }

  .ai-stage-items {
    grid-template-columns: 1fr;
    padding-left: 26px;
  }

  .ai-route-connector {
    height: 20px;
    margin-left: 6px;
  }

  .ai-tool-row {
    padding-top: 22px;
    padding-bottom: 22px;
  }

  .ai-dev-card {
    padding: 22px;
  }

  .ai-choice-panel {
    padding: 24px 20px;
  }
}