.ai-hero {
  max-width: 100%;
  overflow-x: clip;
  padding-top: 82px;
  padding-bottom: 92px;
  border-bottom: 1px solid var(--color-border);
  background:
    radial-gradient(closest-side at 78% 58%, var(--color-neutral-halo), transparent),
    linear-gradient(180deg, var(--color-bg-top), var(--color-bg));
}

.ai-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(360px, 0.76fr);
  align-items: center;
  gap: 76px;
}

.ai-hero-copy h1 {
  max-width: 780px;
  margin: 18px 0 0;
  font-weight: 800;
}

.ai-hero-lede {
  max-width: 42em;
  margin: 24px 0 0;
  font-size: 19px;
}

.ai-hero-actions {
  margin-top: 30px;
}

.ai-signup-note {
  margin: 18px 0 0;
  font-size: 13px;
}

.ai-route-panel {
  padding: 30px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: var(--color-panel);
  box-shadow: var(--shadow-near), var(--shadow-far);
  transform-style: preserve-3d;
}

.ai-panel-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--color-border);
}

.ai-panel-head h2 {
  margin: 6px 0 0;
  font-size: 24px;
}

.ai-path {
  display: grid;
  gap: 0;
  padding: 28px 0;
}

.ai-path-node {
  display: flex;
  min-width: 0;
  align-items: center;
  gap: 14px;
}

.ai-path-node b,
.ai-path-node small {
  display: block;
}

.ai-path-node b {
  color: var(--color-text);
  font-size: 14px;
}

.ai-path-node small {
  margin-top: 2px;
  color: var(--color-muted);
  font-size: 12px;
}

.ai-node-mark {
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
  border: 2px solid var(--color-node);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
}

.ai-path-node.is-active .ai-node-mark {
  border-color: var(--color-accent);
  background: var(--color-accent);
  box-shadow: 0 0 14px var(--color-accent-glow);
}

.ai-path-line {
  width: 2px;
  height: 34px;
  margin-left: 5px;
  background: var(--color-border);
}

.ai-path-line.is-active {
  background: var(--color-accent);
  box-shadow: 0 0 9px var(--color-accent-glow);
}

.ai-fact-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-side);
}

.ai-fact-strip div {
  min-width: 0;
  padding: 13px;
  border-right: 1px solid var(--color-border);
}

.ai-fact-strip div:last-child {
  border-right: 0;
}

.ai-fact-strip dt {
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 10px;
}

.ai-fact-strip dd {
  margin: 5px 0 0;
  color: var(--color-text);
  font-size: 13px;
  font-weight: 700;
}

.ai-guide {
  padding-top: 58px;
  padding-bottom: 104px;
}

.ai-section {
  padding-top: 78px;
  padding-bottom: 78px;
}

.ai-section:first-of-type {
  padding-top: 26px;
}

.ai-principles {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.ai-principles article {
  min-width: 0;
  padding: 30px;
  border-right: 1px solid var(--color-border);
}

.ai-principles article:first-child {
  padding-left: 0;
}

.ai-principles article:last-child {
  padding-right: 0;
  border-right: 0;
}

.ai-principles h3 {
  margin: 10px 0 10px;
  font-size: 21px;
}

.ai-principles p {
  margin-bottom: 0;
}

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

.ai-tool-row {
  display: grid;
  grid-template-columns: minmax(180px, 0.34fr) minmax(0, 1fr);
  gap: 48px;
  padding: 28px 0;
  border-bottom: 1px solid var(--color-border);
}

.ai-tool-name h3 {
  margin: 12px 0 0;
  font-size: 24px;
}

.ai-tool-row p {
  max-width: 52em;
  margin-bottom: 0;
}

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

.ai-reading h3 {
  margin: 34px 0 10px;
  font-size: 21px;
}

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

.ai-reading p {
  margin-bottom: 0;
}

.ai-split {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.ai-mode-card {
  padding: 30px;
}

.ai-mode-card h3 {
  margin: 12px 0 12px;
  font-size: 24px;
}

.ai-mode-card ul,
.ai-dev-grid ul,
.ai-check-panel ul {
  margin: 22px 0 0;
  list-style: none;
}

.ai-mode-card li,
.ai-check-panel li {
  position: relative;
  padding: 9px 0 9px 20px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
}

.ai-mode-card li::before,
.ai-check-panel li::before {
  position: absolute;
  top: 9px;
  left: 0;
  color: var(--color-accent);
  content: "✓";
}

.ai-callout {
  margin-top: 22px;
}

.ai-dev-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--color-border);
}

.ai-dev-grid article {
  padding: 28px;
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.ai-dev-grid article:first-child {
  padding-left: 0;
}

.ai-dev-grid article:last-child {
  padding-right: 0;
  border-right: 0;
}

.ai-dev-grid h3 {
  margin-bottom: 10px;
  font-size: 21px;
}

.ai-dev-grid p {
  margin-bottom: 0;
}

.ai-selection {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(310px, 0.54fr);
  align-items: start;
  gap: 64px;
}

.ai-selection-copy h3 {
  margin-bottom: 14px;
}

.ai-selection-copy p {
  max-width: 50em;
}

.ai-selection-actions {
  margin-top: 30px;
}

.ai-check-panel {
  padding: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: var(--color-panel);
  box-shadow: var(--shadow-far);
}

.ai-check-panel img {
  width: 54px;
  height: 54px;
  padding: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-panel-raised);
}

.ai-check-panel h3 {
  margin: 22px 0 0;
  font-size: 22px;
}

@media (max-width: 1024px) {
  .ai-hero-grid {
    grid-template-columns: minmax(0, 1fr) minmax(330px, 0.8fr);
    gap: 38px;
  }

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

  .ai-principles article,
  .ai-principles article:first-child,
  .ai-principles article:last-child {
    padding: 26px 0;
    border-right: 0;
    border-bottom: 1px solid var(--color-border);
  }

  .ai-principles article:last-child {
    border-bottom: 0;
  }

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

  .ai-dev-grid article,
  .ai-dev-grid article:first-child,
  .ai-dev-grid article:last-child {
    padding: 26px 0;
    border-right: 0;
  }

  .ai-selection {
    gap: 36px;
  }
}

@media (max-width: 768px) {
  .ai-hero {
    padding-top: 56px;
    padding-bottom: 70px;
  }

  .ai-hero-grid,
  .ai-split,
  .ai-selection {
    grid-template-columns: 1fr;
  }

  .ai-route-panel {
    margin-top: 10px;
  }

  .ai-guide {
    padding-top: 42px;
    padding-bottom: 76px;
  }

  .ai-section {
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .ai-tool-row {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .ai-selection {
    gap: 30px;
  }
}

@media (max-width: 640px) {
  .ai-hero {
    max-width: 100%;
    padding-top: 42px;
    padding-bottom: 58px;
  }

  .ai-hero-lede {
    font-size: 16px;
  }

  .ai-route-panel,
  .ai-mode-card,
  .ai-check-panel {
    padding: 22px;
  }

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

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

  .ai-fact-strip div {
    border-right: 0;
    border-bottom: 1px solid var(--color-border);
  }

  .ai-fact-strip div:last-child {
    border-bottom: 0;
  }

  .ai-section {
    padding-top: 54px;
    padding-bottom: 54px;
  }

  .ai-tool-row {
    padding: 24px 0;
  }

  .ai-selection-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .ai-selection-actions .btn,
  .ai-selection-actions .text-link {
    width: 100%;
  }
}