.ai-hero {
  display: grid;
  grid-template-columns: minmax(0, .92fr) minmax(0, 1.08fr);
  gap: 16px;
  padding-top: 26px;
  padding-bottom: 30px;
}

.ai-hero-copy,
.ai-route-board {
  min-width: 0;
  min-height: 520px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-medium);
  box-shadow: var(--shadow-card);
}

.ai-hero-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 48px;
  background: var(--color-panel);
}

.ai-hero-copy h1 {
  margin-top: 20px;
  font-size: clamp(48px, 4.5vw, 64px);
}

.ai-hero-lead {
  max-width: 40em;
  color: var(--color-muted);
  font-size: 17px;
  line-height: 1.85;
}

.ai-hero-actions {
  margin-top: 10px;
  margin-bottom: 28px;
}

.ai-fact-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--color-line);
  list-style: none;
}

.ai-fact-row li {
  min-width: 0;
}

.ai-fact-row strong,
.ai-fact-row span {
  display: block;
}

.ai-fact-row strong {
  color: var(--color-text);
  font-size: 13px;
}

.ai-fact-row span {
  margin-top: 4px;
  color: var(--color-muted);
  font-size: 11px;
  line-height: 1.5;
}

.ai-route-board {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 22px;
  overflow: hidden;
  background-color: var(--color-panel-soft);
  background-image:
    radial-gradient(var(--color-dot) 1px, transparent 1.3px),
    linear-gradient(148deg, var(--color-panel-warm), var(--color-panel-soft));
  background-size: 26px 26px, auto;
}

.ai-board-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .12em;
}

.ai-board-status {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--color-accent-dark);
}

.ai-board-status i {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: var(--radius-pill);
  background: var(--color-accent);
}

.ai-route-stage {
  position: relative;
  flex: 1;
  min-height: 380px;
}

.ai-route-line {
  position: absolute;
  height: 44px;
  border-top: 1px solid var(--color-panel);
  border-bottom: 1px solid var(--color-ink-16);
  box-shadow: var(--shadow-lift);
  transform: rotate(-12deg) skewX(-18deg);
}

.ai-route-line-a {
  right: 36%;
  bottom: 28%;
  left: 2%;
  background: linear-gradient(90deg, var(--color-amber-light), var(--color-amber));
}

.ai-route-line-b {
  right: 16%;
  bottom: 42%;
  left: 31%;
  background: linear-gradient(90deg, var(--color-amber-dark), var(--color-coral));
}

.ai-route-line-c {
  right: 2%;
  bottom: 56%;
  left: 57%;
  background: linear-gradient(90deg, var(--color-coral-dark), var(--color-accent));
}

.ai-route-node {
  position: absolute;
  z-index: 2;
  display: grid;
  min-width: 122px;
  justify-items: center;
  padding: 14px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-small);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
  text-align: center;
}

.ai-route-node b {
  margin-top: 8px;
  font-size: 13px;
}

.ai-route-node small {
  margin-top: 3px;
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: .06em;
}

.ai-node-local {
  bottom: 10%;
  left: 2%;
}

.ai-node-edge {
  bottom: 36%;
  left: 39%;
}

.ai-node-service {
  top: 8%;
  right: 2%;
}

.ai-node-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: var(--radius-small);
  background: var(--color-accent-12);
  color: var(--color-accent);
}

.ai-node-mark svg {
  width: 21px;
  height: 21px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.7;
}

.ai-route-spark {
  position: absolute;
  z-index: 3;
  bottom: 34%;
  left: 38%;
  width: 10px;
  height: 10px;
  border: 2px solid var(--color-panel);
  border-radius: var(--radius-pill);
  background: var(--color-spark);
  box-shadow: var(--shadow-button);
  animation: ai-route-flow 6.5s linear infinite;
}

@keyframes ai-route-flow {
  0% {
    opacity: 0;
    transform: translate(-130px, 58px);
  }

  8% {
    opacity: 1;
  }

  48% {
    transform: translate(42px, -24px);
  }

  86% {
    opacity: 1;
  }

  100% {
    opacity: 0;
    transform: translate(210px, -118px);
  }
}

.ai-tool-tape {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 16px;
  border-top: 1px solid var(--color-line);
}

.ai-tool-tape span {
  padding: 5px 10px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-pill);
  background: var(--color-panel);
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: 10px;
}

.ai-article {
  min-width: 0;
}

.ai-reading {
  max-width: 1040px;
  margin-inline: auto;
}

.ai-reading .section-head {
  max-width: 800px;
}

.ai-reading .section-head > p {
  color: var(--color-muted);
  font-size: 17px;
}

.ai-principle-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.ai-principle {
  position: relative;
  padding-right: 72px;
}

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

.ai-letter {
  position: absolute;
  top: 24px;
  right: 24px;
  display: grid;
  min-width: 38px;
  min-height: 30px;
  place-items: center;
  border-radius: var(--radius-small);
  background: var(--color-accent-12);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 800;
}

.ai-tool-table td {
  color: var(--color-muted);
}

.ai-tool-table td:first-child {
  color: var(--color-accent-dark);
}

.ai-flow {
  display: grid;
  gap: 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-medium);
  background: var(--color-panel);
  box-shadow: var(--shadow-card);
}

.ai-flow section {
  position: relative;
  display: grid;
  grid-template-columns: 82px minmax(0, .55fr) minmax(0, 1.45fr);
  gap: 22px;
  align-items: start;
  padding: 24px;
  border-bottom: 1px solid var(--color-line);
}

.ai-flow section:last-child {
  border-bottom: 0;
}

.ai-flow span {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-pill);
  background: var(--color-accent-12);
  color: var(--color-accent-dark);
  font-size: 12px;
  font-weight: 800;
}

.ai-flow h3 {
  margin-bottom: 0;
  font-size: 20px;
}

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

.ai-split {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.ai-detail-panel {
  padding: 28px;
}

.ai-detail-panel ul,
.ai-selection-main ul {
  display: grid;
  gap: 12px;
  margin-bottom: 0;
  padding-left: 1.25em;
  color: var(--color-muted);
}

.ai-detail-panel li::marker,
.ai-selection-main li::marker {
  color: var(--color-accent);
}

.ai-dev-ledger {
  border-top: 1px solid var(--color-line);
}

.ai-dev-ledger > section {
  display: grid;
  grid-template-columns: minmax(0, .55fr) minmax(0, 1fr) minmax(0, 1fr);
  gap: 26px;
  padding-top: 28px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--color-line);
}

.ai-dev-ledger h3,
.ai-dev-ledger p {
  margin-bottom: 0;
}

.ai-dev-ledger p {
  color: var(--color-muted);
}

.ai-failure-list {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.ai-failure-list .faq-item {
  align-self: start;
}

.ai-tool-notes {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 16px;
}

.ai-tool-notes .card {
  grid-column: span 5;
}

.ai-tool-notes .card:nth-child(3n + 1) {
  grid-column: span 7;
  background: var(--color-panel-warm);
}

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

.ai-selection-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  gap: 16px;
}

.ai-selection-main,
.ai-selection-links {
  padding: 30px;
}

.ai-selection-links {
  background: var(--color-panel-soft);
}

.ai-selection-links p {
  color: var(--color-muted);
}

.ai-selection-links .button-row {
  margin-top: 24px;
}

.ai-refund-note {
  margin-top: 20px;
  margin-bottom: 0;
  padding-top: 18px;
  border-top: 1px solid var(--color-line);
  font-size: 13px;
}

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

  .ai-hero-copy,
  .ai-route-board {
    min-height: auto;
  }

  .ai-route-stage {
    min-height: 390px;
  }

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

  .ai-dev-ledger h3 {
    grid-column: 1 / -1;
  }
}

@media (max-width: 760px) {
  .ai-hero-copy {
    padding: 32px 24px;
  }

  .ai-hero-copy h1 {
    font-size: clamp(30px, 9vw, 40px);
  }

  .ai-fact-row,
  .ai-principle-grid,
  .ai-split,
  .ai-failure-list,
  .ai-selection-grid {
    grid-template-columns: 1fr;
  }

  .ai-fact-row {
    gap: 16px;
  }

  .ai-route-board {
    min-height: 360px;
  }

  .ai-route-stage {
    min-height: 280px;
  }

  .ai-route-node {
    min-width: 104px;
    padding: 10px;
  }

  .ai-node-edge {
    left: 34%;
  }

  .ai-route-node small {
    display: none;
  }

  .ai-flow section {
    grid-template-columns: 68px minmax(0, 1fr);
  }

  .ai-flow p {
    grid-column: 1 / -1;
  }

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

  .ai-dev-ledger h3 {
    grid-column: auto;
  }

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

  .ai-tool-notes .card,
  .ai-tool-notes .card:nth-child(3n + 1) {
    grid-column: auto;
  }
}

@media (max-width: 480px) {
  .ai-hero {
    padding-top: 16px;
  }

  .ai-hero-copy {
    padding: 28px 20px;
  }

  .ai-route-board {
    min-height: 330px;
    padding: 16px;
  }

  .ai-route-stage {
    min-height: 250px;
  }

  .ai-route-node {
    min-width: 88px;
    padding: 8px;
  }

  .ai-node-local {
    left: 0;
  }

  .ai-node-edge {
    left: 35%;
  }

  .ai-node-service {
    right: 0;
  }

  .ai-node-mark {
    width: 30px;
    height: 30px;
  }

  .ai-route-node b {
    font-size: 11px;
  }

  .ai-tool-tape {
    gap: 6px;
  }

  .ai-tool-tape span {
    padding: 4px 7px;
    font-size: 9px;
  }

  .ai-principle {
    padding-right: 24px;
  }

  .ai-letter {
    position: static;
    width: fit-content;
    margin-bottom: 16px;
  }

  .ai-flow section {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .ai-flow span {
    width: fit-content;
    padding-inline: 14px;
  }

  .ai-selection-main,
  .ai-selection-links,
  .ai-detail-panel {
    padding: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .ai-route-spark {
    animation: none;
    opacity: 1;
    transform: none;
  }
}