:root {
  --ai-bg: oklch(0.11 0.07 255);
  --ai-panel: rgba(19, 24, 44, 0.92);
  --ai-border: rgba(255, 255, 255, 0.14);
  --ai-text: oklch(0.97 0.01 260);
  --ai-muted: oklch(0.8 0.03 260);
  --ai-accent: oklch(0.73 0.19 250);
  --ai-accent-2: oklch(0.8 0.17 150);
  --ai-warm: oklch(0.79 0.15 85);
  --ai-rose: oklch(0.76 0.16 10);
}

body.ai-page {
  margin: 0;
  font-family: "Inter", "Plus Jakarta Sans", system-ui, sans-serif;
  color: var(--ai-text);
  background: radial-gradient(circle at 10% 10%, rgba(99, 102, 241, 0.22), transparent 40%),
    radial-gradient(circle at 90% 0%, rgba(16, 185, 129, 0.18), transparent 30%),
    var(--ai-bg);
}

.ai-wrap { max-width: 1040px; margin: 0 auto; padding: 1.2rem 1rem 4rem; }
.ai-nav { display: flex; gap: .75rem; flex-wrap: wrap; margin: .5rem 0 1rem; }
.ai-nav a, .ai-btn {
  border: 1px solid var(--ai-border);
  color: var(--ai-text);
  text-decoration: none;
  padding: .58rem .95rem;
  border-radius: 999px;
  background: rgba(255,255,255,.03);
  font-weight: 600;
  transition: transform .16s ease, border-color .2s ease, background .2s ease, box-shadow .2s ease;
}
.ai-nav a:hover, .ai-btn:hover {
  transform: translateY(-1px);
  border-color: rgba(255,255,255,.24);
  background: rgba(255,255,255,.06);
  box-shadow: 0 10px 24px rgba(4, 8, 24, .18);
}
.ai-nav a.active { border-color: var(--ai-accent); }
.ai-hero, .ai-card {
  background: var(--ai-panel);
  border: 1px solid var(--ai-border);
  border-radius: 1rem;
  box-shadow: 0 16px 40px rgba(4, 8, 24, .4);
}
.ai-hero { padding: 1.4rem 1.3rem; }
.ai-card { margin-top: 1rem; padding: 1.2rem; }
.ai-lead { color: var(--ai-muted); line-height: 1.65; }
.ai-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(260px,1fr)); gap: .9rem; }
.tag { display:inline-block; background: rgba(99,102,241,.18); border:1px solid rgba(99,102,241,.45); border-radius:999px; padding:.22rem .6rem; font-size:.8rem; margin-right:.4rem; }
.diagram {
  margin-top: .8rem; background: rgba(0,0,0,.2); border:1px dashed var(--ai-border); border-radius:.9rem; padding:.8rem; overflow:auto;
}
svg { max-width: 100%; height: auto; }
.term-list li { margin: .5rem 0; color: var(--ai-muted); }
.quiz button { margin-right: .45rem; margin-bottom: .45rem; }
.quiz-result { margin-top: .5rem; color: var(--ai-accent-2); font-weight: 600; }
footer { color: var(--ai-muted); text-align:center; margin-top: 2rem; font-size: .85rem; }

.section-heading {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.section-heading h2 {
  margin: 0;
}

.section-lead {
  margin: .45rem 0 0;
  color: var(--ai-muted);
  line-height: 1.7;
  max-width: 44rem;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
  padding: .42rem .78rem;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,.14);
  background: linear-gradient(135deg, rgba(99, 102, 241, .18), rgba(16, 185, 129, .12));
  color: var(--ai-text);
  font-size: .82rem;
  font-weight: 700;
}

.tradeoff-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.tradeoff-card {
  position: relative;
  overflow: hidden;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding: 1.15rem;
  border-radius: 1rem;
  border: 1px solid rgba(255,255,255,.1);
  background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.025));
  box-shadow: inset 0 1px 0 rgba(255,255,255,.05), 0 16px 28px rgba(4, 8, 24, .22);
  transition: transform .2s ease, border-color .2s ease, box-shadow .2s ease;
}

.tradeoff-card::after {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, rgba(255,255,255,.22), rgba(255,255,255,0));
}

.tradeoff-card:hover {
  transform: translateY(-3px);
  border-color: rgba(255,255,255,.18);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.06), 0 22px 34px rgba(4, 8, 24, .28);
}

.tradeoff-icon {
  flex: 0 0 auto;
  width: 3rem;
  height: 3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: .9rem;
  color: var(--ai-text);
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.12);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.08);
}

.tradeoff-icon svg {
  width: 1.35rem;
  height: 1.35rem;
}

.strategy-a .tradeoff-icon {
  background: linear-gradient(135deg, rgba(245, 158, 11, .22), rgba(99, 102, 241, .18));
  color: var(--ai-warm);
}

.strategy-b .tradeoff-icon {
  background: linear-gradient(135deg, rgba(99, 102, 241, .24), rgba(45, 212, 191, .16));
  color: var(--ai-accent);
}

.strategy-c .tradeoff-icon {
  background: linear-gradient(135deg, rgba(16, 185, 129, .22), rgba(59, 130, 246, .16));
  color: var(--ai-accent-2);
}

.tradeoff-body {
  min-width: 0;
}

.tradeoff-topline {
  color: var(--ai-muted);
  font-size: .78rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  font-weight: 700;
}

.tradeoff-body h3 {
  margin: .22rem 0 .5rem;
  font-size: 1.08rem;
}

.tradeoff-summary {
  margin: 0;
  line-height: 1.72;
  color: var(--ai-text);
}

.tradeoff-points {
  margin: .8rem 0 0;
  padding-left: 1.15rem;
  color: var(--ai-muted);
}

.tradeoff-points li {
  margin: .42rem 0;
  line-height: 1.62;
}

.tradeoff-flow {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .45rem;
  margin-top: .85rem;
  padding: .62rem .78rem;
  border-radius: .9rem;
  border: 1px solid rgba(255,255,255,.1);
  background: rgba(0,0,0,.18);
  color: var(--ai-text);
  font-size: .92rem;
  font-weight: 600;
}

.flow-arrow {
  color: var(--ai-accent-2);
}

.planning-flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
  gap: .8rem;
  align-items: stretch;
  margin: 1rem 0 1.1rem;
}

.planning-step {
  position: relative;
  padding: 1rem;
  border-radius: 1rem;
  border: 1px solid rgba(255,255,255,.1);
  background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.025));
  box-shadow: inset 0 1px 0 rgba(255,255,255,.05), 0 12px 24px rgba(4, 8, 24, .2);
}

.planning-step-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  margin-bottom: .85rem;
}

.planning-node {
  width: 2.75rem;
  height: 2.75rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: .95rem;
  border: 1px solid rgba(255,255,255,.12);
  background: rgba(255,255,255,.08);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.08);
}

.planning-node svg {
  width: 1.3rem;
  height: 1.3rem;
}

.planning-index {
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .08em;
  color: var(--ai-muted);
}

.planning-step-body h3 {
  margin: 0 0 .45rem;
  font-size: 1rem;
}

.planning-step-body p {
  margin: 0;
  color: var(--ai-muted);
  line-height: 1.68;
  font-size: .94rem;
}

.planning-connector {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  color: rgba(255,255,255,.55);
  min-width: 2rem;
}

.planning-connector span {
  display: block;
  width: 1px;
  height: 100%;
  min-height: 1.25rem;
  background: linear-gradient(180deg, rgba(255,255,255,.18), rgba(99,102,241,.42), rgba(16,185,129,.18));
}

.planning-connector svg {
  width: 1.25rem;
  height: 1.25rem;
  flex: 0 0 auto;
}

.planning-tags {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem;
  margin-top: .75rem;
}

.planning-tags span {
  padding: .28rem .55rem;
  border-radius: 999px;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.1);
  color: var(--ai-text);
  font-size: .78rem;
  font-weight: 700;
}

.step-user .planning-node {
  background: linear-gradient(135deg, rgba(99, 102, 241, .22), rgba(129, 140, 248, .12));
  color: var(--ai-accent);
}

.step-brain .planning-node {
  background: linear-gradient(135deg, rgba(45, 212, 191, .18), rgba(99, 102, 241, .18));
  color: var(--ai-accent-2);
}

.step-tools .planning-node {
  background: linear-gradient(135deg, rgba(245, 158, 11, .22), rgba(251, 191, 36, .12));
  color: var(--ai-warm);
}

.step-review .planning-node {
  background: linear-gradient(135deg, rgba(244, 114, 182, .18), rgba(99, 102, 241, .18));
  color: var(--ai-rose);
}

.step-answer .planning-node {
  background: linear-gradient(135deg, rgba(16, 185, 129, .22), rgba(45, 212, 191, .12));
  color: var(--ai-accent-2);
}

@media (max-width: 1080px) {
  .planning-flow {
    grid-template-columns: minmax(0, 1fr);
  }

  .planning-connector {
    flex-direction: row;
    justify-content: flex-start;
    gap: .6rem;
    padding-left: 1rem;
  }

  .planning-connector span {
    width: 2.2rem;
    height: 1px;
    min-height: 0;
    background: linear-gradient(90deg, rgba(255,255,255,.18), rgba(99,102,241,.42), rgba(16,185,129,.18));
  }

  .planning-connector svg {
    transform: rotate(90deg);
  }
}

@media (max-width: 720px) {
  .section-heading {
    flex-direction: column;
  }

  .section-badge {
    white-space: normal;
  }

  .tradeoff-card {
    flex-direction: column;
  }

  .tradeoff-icon {
    width: 2.8rem;
    height: 2.8rem;
  }

  .planning-step {
    padding: .95rem;
  }
}


.chapter-grid {
  align-items: stretch;
}

.chapter-card {
  display: flex;
  flex-direction: column;
  gap: .85rem;
}

.chapter-card .ai-btn {
  margin-top: auto;
  align-self: flex-start;
}

.chapter-kicker {
  display: inline-flex;
  align-items: center;
  padding: .28rem .6rem;
  border-radius: 999px;
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.12);
  color: var(--ai-muted);
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.chapter-card--accent {
  background: linear-gradient(180deg, rgba(99,102,241,.13), rgba(255,255,255,.03));
}

.chapter-card--accent-2 {
  background: linear-gradient(180deg, rgba(16,185,129,.12), rgba(255,255,255,.03));
}

.mini-card {
  padding: 1rem;
  border-radius: 1rem;
  border: 1px solid rgba(255,255,255,.1);
  background: linear-gradient(180deg, rgba(255,255,255,.05), rgba(255,255,255,.02));
  box-shadow: inset 0 1px 0 rgba(255,255,255,.04);
}

.mini-card h3 {
  margin: 0 0 .55rem;
}

.mini-card p {
  margin: 0;
  color: var(--ai-muted);
  line-height: 1.68;
}

.mini-card--glow {
  box-shadow: inset 0 1px 0 rgba(255,255,255,.04), 0 16px 30px rgba(4, 8, 24, .16);
}

.compare-table {
  display: grid;
  gap: .65rem;
}

.compare-row {
  display: grid;
  grid-template-columns: minmax(110px, 1fr) minmax(0, 1.2fr) minmax(0, 1.2fr);
  gap: .75rem;
  padding: .9rem 1rem;
  border-radius: 1rem;
  border: 1px solid rgba(255,255,255,.1);
  background: linear-gradient(180deg, rgba(255,255,255,.05), rgba(255,255,255,.02));
}

.compare-row > div {
  line-height: 1.68;
}

.compare-head {
  background: linear-gradient(135deg, rgba(99,102,241,.18), rgba(16,185,129,.1));
  border-color: rgba(255,255,255,.14);
  font-weight: 800;
}

.compare-row:not(.compare-head) > div:first-child {
  color: var(--ai-text);
  font-weight: 700;
}

.compare-row:not(.compare-head) > div:not(:first-child) {
  color: var(--ai-muted);
}

@media (max-width: 720px) {
  .compare-row {
    grid-template-columns: 1fr;
  }
}


.chapter-card--accent-3 {
  background: linear-gradient(180deg, rgba(244,114,182,.12), rgba(255,255,255,.03));
}


.chapter-card--accent-4 {
  background: linear-gradient(180deg, rgba(245,158,11,.12), rgba(255,255,255,.03));
}


.chapter-bridge,
.chapter-next {
  background: linear-gradient(180deg, rgba(255,255,255,.055), rgba(255,255,255,.025));
}

.chapter-bridge h2,
.chapter-next h2 {
  margin-top: 0;
  margin-bottom: .55rem;
}


.chapter-card--accent-5 {
  background: linear-gradient(180deg, rgba(239,68,68,.12), rgba(255,255,255,.03));
}