@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=JetBrains+Mono:wght@400;500&family=Space+Grotesk:wght@500;600;700&display=swap');

:root {
  --ink: #E4E7F2;
  --ink-deep: #D8DCEB;
  --surface: #F3F1FA;
  --surface-raised: #FAF8FF;
  --surface-tint: #ECEAF6;
  --border: #C9CDDF;
  --accent: #5B52E8;
  --accent-soft: #8B84F0;
  --accent-warm: #D94F4F;
  --accent-teal: #3D9E9A;
  --text: #1C1C32;
  --muted: #555570;
  --accent-glow: rgba(91, 82, 232, 0.22);
  --warm-glow: rgba(217, 79, 79, 0.15);
  --nav-h: 64px;
  --radius: 12px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow: 0 2px 8px rgba(60, 55, 120, 0.07), 0 1px 2px rgba(60, 55, 120, 0.05);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }
body {
  font-family: 'Inter', system-ui, sans-serif;
  background: linear-gradient(165deg, #E0E4F0 0%, #E8EAF4 35%, #DDD8EE 70%, #E2E8F0 100%);
  background-attachment: fixed;
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

h1, h2, h3, h4, .display { font-family: 'Space Grotesk', sans-serif; }
code, pre, .mono { font-family: 'JetBrains Mono', monospace; }

/* ── Nav ── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--nav-h);
  background: rgba(243, 241, 250, 0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 1.5rem;
}
.nav-logo {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700; font-size: 1rem;
  color: var(--accent); text-decoration: none;
  white-space: nowrap;
}
.nav-links {
  display: flex; gap: 0.25rem; list-style: none;
  overflow-x: auto; scrollbar-width: none;
}
.nav-links::-webkit-scrollbar { display: none; }
.nav-links a {
  color: var(--muted); text-decoration: none;
  font-size: 0.75rem; font-weight: 500;
  padding: 0.4rem 0.65rem; border-radius: 6px;
  white-space: nowrap; transition: color var(--transition), background var(--transition);
}
.nav-links a:hover, .nav-links a.active {
  color: var(--accent); background: rgba(91, 82, 232, 0.1);
}
.nav-toggle {
  display: none; background: none; border: 1px solid var(--border);
  color: var(--text); padding: 0.4rem 0.6rem; border-radius: 6px; cursor: pointer;
  font-size: 1.1rem;
}

/* ── Hero ── */
.hero {
  position: relative; min-height: 100vh;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  text-align: center; padding: calc(var(--nav-h) + 2rem) 1.5rem 4rem;
  overflow: hidden;
  background: linear-gradient(180deg, rgba(224,228,240,0.5) 0%, rgba(221,216,238,0.35) 100%);
}
.hero-grid {
  position: absolute; inset: 0; z-index: 0;
  background-image: radial-gradient(circle, rgba(91,82,232,0.16) 1px, transparent 1px);
  background-size: 32px 32px;
  animation: gridDrift 20s linear infinite;
}
.hero::after {
  content: ''; position: absolute; inset: 0; z-index: 0;
  background: radial-gradient(ellipse at 50% 80%, rgba(91,82,232,0.08) 0%, transparent 60%);
}
@keyframes gridDrift {
  0% { transform: translate(0, 0); }
  100% { transform: translate(32px, 32px); }
}
.hero-content { position: relative; z-index: 1; max-width: 800px; }
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700; line-height: 1.15; margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--text) 0%, var(--accent) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-sub {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--muted); max-width: 640px; margin: 0 auto 2rem;
}
.typewriter-wrap {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  color: var(--accent-warm); min-height: 2rem;
}
.typewriter-cursor {
  display: inline-block; width: 2px; height: 1.2em;
  background: var(--accent-warm); margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 0.8s step-end infinite;
}
@keyframes blink { 50% { opacity: 0; } }
.hero-scroll {
  position: absolute; bottom: 2rem; left: 50%; transform: translateX(-50%);
  color: var(--muted); font-size: 0.8rem;
  animation: bounce 2s ease infinite;
}
@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ── Layout ── */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }
section { padding: 5rem 0; }
.section-header { text-align: center; margin-bottom: 3rem; }
.section-header h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem); margin-bottom: 0.5rem;
}
.section-header p { color: var(--muted); max-width: 640px; margin: 0 auto; }

/* ── Intro Sections ── */
.intro-block {
  background: var(--surface-raised);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2.5rem;
  margin-bottom: 2.5rem;
  box-shadow: var(--shadow);
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.intro-block.visible { opacity: 1; transform: translateY(0); }
.intro-block h2 {
  font-size: clamp(1.4rem, 2.8vw, 1.85rem);
  margin-bottom: 1rem; color: var(--text);
}
.intro-block h3 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.05rem; margin: 1.75rem 0 0.75rem;
  color: var(--accent);
}
.intro-lead {
  font-size: 1.05rem; color: var(--muted); line-height: 1.75;
  margin-bottom: 1.25rem;
}
.intro-text { color: var(--muted); font-size: 0.95rem; line-height: 1.75; margin-bottom: 1rem; }
.pillar-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem; margin: 1.5rem 0;
}
.pillar {
  background: linear-gradient(145deg, #EDE9F8 0%, #E4E8F4 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}
.pillar-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; color: var(--accent); font-weight: 500;
  margin-bottom: 0.4rem;
}
.pillar h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem; margin-bottom: 0.35rem;
}
.pillar p { font-size: 0.85rem; color: var(--muted); line-height: 1.55; }

/* Timeline */
.timeline { margin: 1.5rem 0; position: relative; padding-left: 1.5rem; }
.timeline::before {
  content: ''; position: absolute; left: 5px; top: 8px; bottom: 8px;
  width: 2px; background: linear-gradient(180deg, var(--accent), var(--accent-teal));
}
.tl-item {
  position: relative; padding-bottom: 1.5rem; padding-left: 1.25rem;
}
.tl-item:last-child { padding-bottom: 0; }
.tl-item::before {
  content: ''; position: absolute; left: -1.5rem; top: 6px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--surface-raised); border: 2px solid var(--accent);
}
.tl-year {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem; color: var(--accent-warm); font-weight: 500;
  margin-bottom: 0.2rem;
}
.tl-item h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem; margin-bottom: 0.3rem;
}
.tl-item p { font-size: 0.88rem; color: var(--muted); line-height: 1.6; }

/* Types divider */
.types-divider {
  text-align: center; padding: 3rem 0 1rem;
  opacity: 0; transform: translateY(20px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.types-divider.visible { opacity: 1; transform: translateY(0); }
.types-divider .divider-line {
  width: 60px; height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-warm));
  margin: 0 auto 1rem; border-radius: 2px;
}
.types-divider h2 {
  font-size: clamp(1.6rem, 3vw, 2.1rem); margin-bottom: 0.5rem;
}
.types-divider p { color: var(--muted); max-width: 560px; margin: 0 auto; font-size: 0.95rem; }

/* ── RAG Cards ── */
.rag-card {
  background: var(--surface-raised);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2.5rem;
  margin-bottom: 3rem;
  box-shadow: var(--shadow);
  opacity: 0; transform: translateY(32px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.rag-card.visible, .observe.visible, .intro-block.visible { opacity: 1; transform: translateY(0); }
.observe {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.rag-badge {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; font-weight: 500;
  text-transform: uppercase; letter-spacing: 0.08em;
  background: rgba(91, 82, 232, 0.08);
  color: var(--accent); border: 1px solid rgba(91, 82, 232, 0.25);
  padding: 0.3rem 0.8rem; border-radius: 100px;
  margin-bottom: 0.75rem;
}
.rag-card h2 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  margin-bottom: 1rem;
}
.concept { color: var(--muted); font-size: 1.05rem; margin-bottom: 2rem; line-height: 1.7; }

/* ── Flow Diagrams ── */
.flow-diagram {
  background: linear-gradient(135deg, #E6E2F4 0%, #DDE3F0 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
  overflow-x: auto;
}
.flow-diagram svg { display: block; margin: 0 auto; min-width: 500px; }
.flow-node {
  fill: #F8F6FD; stroke: #B8BDD4; stroke-width: 1.5;
  transition: fill 0.4s, stroke 0.4s, filter 0.4s;
}
.flow-node.lit {
  fill: rgba(91, 82, 232, 0.12);
  stroke: var(--accent);
  filter: drop-shadow(0 0 6px var(--accent-glow));
}
.flow-node.lit-warm {
  fill: rgba(232, 85, 85, 0.1);
  stroke: var(--accent-warm);
  filter: drop-shadow(0 0 6px var(--warm-glow));
}
.flow-loop-box {
  fill: none; stroke: #C8CBDA; stroke-width: 1.5; stroke-dasharray: 5 4;
  transition: stroke 0.4s;
}
.flow-loop-box.lit { stroke: var(--accent); }
.flow-label {
  fill: var(--text); font-family: 'JetBrains Mono', monospace;
  font-size: 10px; text-anchor: middle;
}
.flow-label-muted {
  fill: var(--muted); font-family: 'JetBrains Mono', monospace;
  font-size: 9px; text-anchor: middle;
}
.flow-arrow {
  stroke: var(--muted); stroke-width: 1.5; fill: none;
  stroke-dasharray: 6 4;
  transition: stroke 0.4s;
}
.flow-arrow.lit { stroke: var(--accent); }
.flow-arrow.lit-warm { stroke: var(--accent-warm); }

/* ── Stepper ── */
.stepper { display: flex; flex-direction: column; gap: 0; margin-bottom: 2rem; }
.step {
  display: flex; gap: 1rem; position: relative;
  padding-bottom: 1.5rem;
}
.step:last-child { padding-bottom: 0; }
.step::before {
  content: ''; position: absolute; left: 15px; top: 32px; bottom: 0;
  width: 2px; background: var(--border);
}
.step:last-child::before { display: none; }
.step-num {
  flex-shrink: 0; width: 32px; height: 32px;
  background: rgba(91, 82, 232, 0.08);
  border: 1px solid rgba(91, 82, 232, 0.3);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem; font-weight: 500; color: var(--accent);
  position: relative; z-index: 1;
}
.step-body h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem; margin-bottom: 0.25rem;
}
.step-body p { color: var(--muted); font-size: 0.9rem; }

/* ── Component Cards ── */
.components {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem; margin-bottom: 2rem;
}
.comp-card {
  background: linear-gradient(145deg, #EDE9F8 0%, #E8ECF5 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}
.comp-card:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: var(--shadow); }
.comp-icon { font-size: 1.5rem; margin-bottom: 0.5rem; }
.comp-card h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.9rem; margin-bottom: 0.35rem;
}
.comp-card p { color: var(--muted); font-size: 0.8rem; line-height: 1.5; }

/* ── Strengths / Limitations ── */
.pros-cons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem; margin-bottom: 2rem;
}
.pros, .cons {
  background: linear-gradient(145deg, #EDE9F8 0%, #E8ECF5 100%);
  border-radius: var(--radius);
  padding: 1.25rem;
}
.pros { border: 1px solid rgba(91, 82, 232, 0.2); }
.cons { border: 1px solid rgba(232, 85, 85, 0.2); }
.pros h4 { color: var(--accent); font-size: 0.85rem; margin-bottom: 0.75rem; }
.cons h4 { color: var(--accent-warm); font-size: 0.85rem; margin-bottom: 0.75rem; }
.pros li, .cons li {
  font-size: 0.85rem; color: var(--muted);
  margin-bottom: 0.4rem; list-style: none;
  padding-left: 1.2rem; position: relative;
}
.pros li::before { content: '✓'; position: absolute; left: 0; color: var(--accent); }
.cons li::before { content: '✗'; position: absolute; left: 0; color: var(--accent-warm); }

/* ── Use Case ── */
.use-case {
  background: rgba(91, 82, 232, 0.05);
  border: 1px solid rgba(91, 82, 232, 0.15);
  border-radius: var(--radius);
  padding: 1.5rem; margin-bottom: 1.5rem;
}
.use-case h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1rem; margin-bottom: 0.75rem; color: var(--accent);
}
.use-case .industry {
  font-size: 0.8rem; color: var(--accent-warm);
  font-family: 'JetBrains Mono', monospace;
  margin-bottom: 0.5rem;
}
.use-case p { color: var(--muted); font-size: 0.9rem; margin-bottom: 0.75rem; }

/* ── Code Blocks ── */
pre {
  background: #E4E8F2;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  overflow-x: auto;
  font-size: 0.78rem;
  line-height: 1.7;
  margin-top: 1rem;
}
.t-kw { color: #7C3AED; }
.t-fn { color: #2563EB; }
.t-str { color: #059669; }
.t-cm { color: #6B7280; font-style: italic; }
.t-var { color: #1E293B; }
.t-num { color: #D97706; }
.t-cls { color: #B45309; }
.t-op { color: #0891B2; }

/* ── Callout ── */
.callout {
  background: linear-gradient(135deg, rgba(91,82,232,0.06), rgba(232,85,85,0.04));
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1rem 1.25rem;
  font-size: 0.9rem;
}
.callout strong { color: var(--accent); }

/* ── Comparison Table ── */
.compare-section { padding: 5rem 0; }
.table-wrap {
  overflow-x: auto;
  border-radius: 16px;
  background: var(--surface-raised);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
table {
  width: 100%; border-collapse: collapse;
  font-size: 0.85rem;
}
thead th {
  background: rgba(91, 82, 232, 0.08);
  color: var(--accent);
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 600; font-size: 0.8rem;
  padding: 1rem; text-align: left;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
tbody td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
}
tbody tr { transition: background var(--transition); }
tbody tr:hover { background: rgba(91, 82, 232, 0.06); }
tbody td:first-child {
  color: var(--text); font-weight: 500;
  font-family: 'Space Grotesk', sans-serif;
}

/* ── Decision Flow ── */
.decision-section { padding: 5rem 0 6rem; }
.decision-box {
  background: var(--surface-raised);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2.5rem;
  max-width: 860px; margin: 0 auto;
  box-shadow: var(--shadow);
}
.q-block { margin-bottom: 2rem; }
.q-block h3 {
  font-size: 1rem; margin-bottom: 0.35rem;
}
.q-hint {
  font-size: 0.85rem; color: var(--muted); margin-bottom: 1rem;
}
.q-options {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.65rem;
}
.q-btn {
  background: linear-gradient(145deg, #EDE9F8 0%, #E8ECF5 100%);
  border: 1px solid var(--border);
  color: var(--text); padding: 0.75rem 1rem;
  border-radius: 8px; cursor: pointer;
  font-family: 'Inter', sans-serif; font-size: 0.85rem;
  text-align: left; line-height: 1.4;
  transition: all var(--transition);
}
.q-btn span { display: block; font-size: 0.75rem; color: var(--muted); margin-top: 0.2rem; }
.q-btn:hover { background: rgba(91, 82, 232, 0.08); border-color: var(--accent); }
.q-btn.selected { background: var(--accent); border-color: var(--accent); color: #fff; }
.q-btn.selected span { color: rgba(255,255,255,0.8); }
.q-btn:disabled:not(.selected) { opacity: 0.45; cursor: not-allowed; }
.decision-result {
  display: none; margin-top: 2rem;
  padding: 1.5rem;
  background: rgba(91, 82, 232, 0.06);
  border: 1px solid rgba(91, 82, 232, 0.25);
  border-radius: var(--radius);
  text-align: left;
}
.decision-result.show { display: block; animation: fadeUp 0.5s ease; }
.decision-result h3 {
  font-size: 1.3rem; color: var(--accent); margin-bottom: 0.5rem;
}
.decision-result p { color: var(--muted); font-size: 0.9rem; margin-bottom: 0.75rem; }
.result-tags {
  display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.75rem;
}
.result-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; padding: 0.25rem 0.6rem;
  background: rgba(91, 82, 232, 0.1);
  border: 1px solid rgba(91, 82, 232, 0.2);
  border-radius: 100px; color: var(--accent);
}
.decision-reset {
  margin-top: 1rem;
  display: inline-block;
  background: none; border: 1px solid var(--border);
  color: var(--muted); padding: 0.5rem 1rem;
  border-radius: 6px; cursor: pointer; font-size: 0.85rem;
  transition: all var(--transition);
}
.decision-reset:hover { border-color: var(--accent); color: var(--text); }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ── Footer ── */
footer {
  text-align: center; padding: 2rem 1.5rem;
  border-top: 1px solid var(--border);
  background: linear-gradient(180deg, var(--surface-tint) 0%, var(--ink-deep) 100%);
}
.footer-copyright {
  color: var(--muted); font-size: 0.8rem; line-height: 1.7;
  max-width: 720px; margin: 0 auto;
}
.footer-copyright a {
  color: var(--accent); text-decoration: none; font-weight: 600;
}
.footer-copyright a:hover { text-decoration: underline; }

/* ── Subsection labels ── */
.sub-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--muted);
  margin-bottom: 0.75rem; margin-top: 0.5rem;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute;
    top: var(--nav-h); left: 0; right: 0;
    flex-direction: column; background: rgba(243,241,250,0.98);
    border-bottom: 1px solid var(--border);
    padding: 1rem; gap: 0.25rem;
  }
  .nav-links.open { display: flex; }
  .nav-links a { font-size: 0.85rem; padding: 0.6rem 1rem; }
  .pros-cons { grid-template-columns: 1fr; }
  .rag-card { padding: 1.5rem; }
  .flow-diagram svg { min-width: 400px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
  .hero-grid { animation: none; }
  .rag-card, .observe, .intro-block { opacity: 1; transform: none; }
}