:root {
  --bg: #f4f6fb;
  --panel: rgba(255,255,255,0.82);
  --panel-strong: #ffffff;
  --text: #122033;
  --muted: #5f6b7b;
  --border: rgba(18,32,51,0.09);
  --accent: #5168ff;
  --accent-2: #8a4bff;
  --accent-soft: rgba(81,104,255,0.10);
  --success: #139c71;
  --warn: #d86f30;
  --shadow: 0 24px 60px rgba(23,35,61,0.08);
  --radius: 24px;
  --radius-sm: 16px;
  --code: rgba(18,32,51,0.06);
  --grid: linear-gradient(to right, rgba(81,104,255,0.06) 1px, transparent 1px), linear-gradient(to bottom, rgba(81,104,255,0.06) 1px, transparent 1px);
}

html[data-theme="dark"] {
  --bg: #0a1017;
  --panel: rgba(17,25,37,0.82);
  --panel-strong: #101924;
  --text: #ecf2ff;
  --muted: #9eb0c8;
  --border: rgba(255,255,255,0.08);
  --accent: #7f95ff;
  --accent-2: #ba88ff;
  --accent-soft: rgba(127,149,255,0.14);
  --success: #29c08f;
  --warn: #f7a45d;
  --shadow: 0 24px 60px rgba(0,0,0,0.34);
  --code: rgba(255,255,255,0.07);
  --grid: linear-gradient(to right, rgba(127,149,255,0.10) 1px, transparent 1px), linear-gradient(to bottom, rgba(127,149,255,0.10) 1px, transparent 1px);
}

@media (prefers-color-scheme: dark) {
  html:not([data-theme]) {
    --bg: #0a1017;
    --panel: rgba(17,25,37,0.82);
    --panel-strong: #101924;
    --text: #ecf2ff;
    --muted: #9eb0c8;
    --border: rgba(255,255,255,0.08);
    --accent: #7f95ff;
    --accent-2: #ba88ff;
    --accent-soft: rgba(127,149,255,0.14);
    --success: #29c08f;
    --warn: #f7a45d;
    --shadow: 0 24px 60px rgba(0,0,0,0.34);
    --code: rgba(255,255,255,0.07);
    --grid: linear-gradient(to right, rgba(127,149,255,0.10) 1px, transparent 1px), linear-gradient(to bottom, rgba(127,149,255,0.10) 1px, transparent 1px);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at top, rgba(81,104,255,0.12), transparent 30%),
    radial-gradient(circle at 90% 12%, rgba(138,75,255,0.10), transparent 26%),
    var(--bg);
  font: 16px/1.7 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
button, input { font: inherit; }

.theme-toggle {
  position: fixed;
  top: 16px;
  right: 16px;
  z-index: 40;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  border-radius: 999px;
  padding: 10px 14px;
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
  cursor: pointer;
}

.page-shell {
  width: min(1400px, calc(100vw - 24px));
  margin: 0 auto;
  padding: 36px 0 96px;
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 28px;
}

.rail {
  position: relative;
}

.rail-card {
  position: sticky;
  top: 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
  padding: 22px;
}

.rail-brand {
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
}

.rail-copy {
  color: var(--muted);
  margin: 0 0 18px;
}

.toc {
  display: grid;
  gap: 4px;
}

.toc a {
  padding: 9px 12px;
  border-radius: 12px;
  color: var(--muted);
  border: 1px solid transparent;
  transition: .18s ease;
}

.toc a:hover,
.toc a.active {
  color: var(--text);
  text-decoration: none;
  border-color: var(--border);
  background: var(--accent-soft);
}

.content {
  display: grid;
  gap: 22px;
}

.panel {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
  padding: 30px;
  overflow: hidden;
}

.panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: var(--grid);
  background-size: 34px 34px;
  mask-image: linear-gradient(to bottom, rgba(0,0,0,0.16), transparent 58%);
  pointer-events: none;
}

.panel > * { position: relative; z-index: 1; }

.hero {
  padding: 38px;
}

.hero-grid,
.two-col,
.demo-layout,
.architecture-grid,
.results-grid,
.math-grid,
.three-up {
  display: grid;
  gap: 22px;
}

.hero-grid { grid-template-columns: minmax(0, 1.2fr) minmax(320px, .8fr); align-items: center; }
.two-col { grid-template-columns: minmax(0, 1.1fr) minmax(280px, .9fr); }
.demo-layout { grid-template-columns: minmax(0, 1.2fr) 300px; align-items: start; }
.demo-layout.compact { grid-template-columns: minmax(0, 1fr) 290px; }
.architecture-grid { grid-template-columns: minmax(0, 1fr) 360px; align-items: start; }
.results-grid { grid-template-columns: minmax(0, 1.12fr) minmax(260px, .88fr); align-items: start; }
.math-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.three-up { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.eyebrow {
  text-transform: uppercase;
  letter-spacing: .13em;
  font-size: 12px;
  font-weight: 800;
  color: var(--accent-2);
}

h1 {
  font-size: clamp(2.6rem, 6vw, 4.6rem);
  line-height: .98;
  letter-spacing: -0.05em;
  margin: 12px 0 16px;
}

h2 {
  font-size: clamp(1.7rem, 3vw, 2.5rem);
  line-height: 1.08;
  letter-spacing: -0.04em;
  margin: 0;
}

h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

p { margin: 0 0 12px; }
ul, ol { margin: 0; padding-left: 1.1rem; }

.lede {
  font-size: 1.1rem;
  color: var(--text);
  max-width: 64ch;
}

.byline,
.section-intro,
.muted {
  color: var(--muted);
}

.section-heading {
  display: grid;
  gap: 8px;
  margin-bottom: 18px;
}

.hero-actions,
.pill-row,
.control-row,
.metric-tabs,
.stage-buttons,
.takeaway-list,
.value-grid,
.hero-points,
.stats-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.button,
.token-button,
.metric-tabs button,
.stage-buttons button {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 10px 14px;
  background: var(--panel-strong);
  color: var(--text);
  cursor: pointer;
  transition: .18s ease;
}

.button:hover,
.token-button:hover,
.metric-tabs button:hover,
.stage-buttons button:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

.button.primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
  color: white;
}

.button.ghost,
.metric-tabs button,
.stage-buttons button {
  background: transparent;
}

.metric-tabs button.is-active,
.stage-buttons button.is-active,
.token-button.is-active {
  background: linear-gradient(135deg, var(--accent-soft), rgba(138,75,255,0.10));
  border-color: rgba(81,104,255,0.28);
  color: var(--text);
}

.pill {
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 12px;
  font-weight: 700;
  background: var(--accent-soft);
  color: var(--accent);
}

.hero-stage,
.side-note,
.callout,
.stat-card,
.math-card,
.stage-card,
.viz-panel,
.mini-card,
.takeaway-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.4);
  padding: 18px;
}

html[data-theme="dark"] .hero-stage,
html[data-theme="dark"] .side-note,
html[data-theme="dark"] .callout,
html[data-theme="dark"] .stat-card,
html[data-theme="dark"] .math-card,
html[data-theme="dark"] .stage-card,
html[data-theme="dark"] .viz-panel,
html[data-theme="dark"] .mini-card,
html[data-theme="dark"] .takeaway-card {
  background: rgba(255,255,255,0.02);
}

.callout.strong {
  border-color: rgba(81,104,255,0.26);
  background: linear-gradient(135deg, rgba(81,104,255,0.12), rgba(138,75,255,0.08));
}

.hero-stage-copy {
  font-weight: 700;
  margin-bottom: 8px;
}

.hero-points {
  padding-left: 1rem;
  color: var(--muted);
}

.hero-tokens {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.hero-token {
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  border: 1px solid rgba(81,104,255,0.18);
  font-size: 14px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.stat-card { padding: 20px; }
.stat-value {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  line-height: 1;
  font-weight: 800;
  letter-spacing: -0.04em;
  margin-bottom: 8px;
}
.stat-label { color: var(--muted); font-size: .95rem; }

.stacked-cards { display: grid; gap: 12px; }
.mini-card.warn { border-color: rgba(216,111,48,0.34); }
.mini-card.accent { border-color: rgba(81,104,255,0.28); }
.mini-card.success { border-color: rgba(19,156,113,0.28); }

.token-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.viz-panel { padding: 14px; margin-top: 12px; }
.viz-panel.wide { padding: 16px; }
.viz-svg {
  width: 100%;
  height: auto;
  display: block;
}

.demo-note,
.inline-code {
  background: var(--code);
  border-radius: 12px;
  padding: 10px 12px;
}

.inline-code {
  display: inline-block;
  padding: 1px 6px;
  border-radius: 8px;
}

.ranked-list {
  display: grid;
  gap: 10px;
  margin-top: 14px;
  padding-left: 1.2rem;
}

.stack-visual {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 56px minmax(0, 1fr);
  align-items: stretch;
  gap: 12px;
}

.stack-lane {
  display: grid;
  gap: 10px;
  align-content: start;
}

.stack-title {
  font-weight: 700;
  color: var(--muted);
}

.stack-node {
  padding: 14px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: rgba(81,104,255,0.06);
  transition: .2s ease;
}

.stack-node.is-active {
  transform: translateY(-2px) scale(1.01);
  border-color: rgba(81,104,255,0.4);
  background: linear-gradient(135deg, rgba(81,104,255,0.18), rgba(138,75,255,0.12));
  box-shadow: inset 0 0 0 1px rgba(255,255,255,0.08);
}

.muted-node {
  background: transparent;
  color: var(--muted);
}

.stack-arrow {
  display: grid;
  place-items: center;
  font-size: 2rem;
  color: var(--accent);
}

.control-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.control-row label {
  display: grid;
  gap: 8px;
  color: var(--muted);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.katex-block {
  overflow-x: auto;
  padding-bottom: 6px;
}

.value-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.value-chip {
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--accent-soft);
  padding: 10px 12px;
}

.value-chip strong {
  display: block;
  font-size: .8rem;
  color: var(--muted);
  margin-bottom: 4px;
}

.takeaway-list {
  display: grid;
  gap: 12px;
}

.takeaway-card {
  display: grid;
  grid-template-columns: 42px 1fr;
  align-items: start;
  gap: 14px;
}

.takeaway-card strong {
  font-size: 1.5rem;
  line-height: 1;
  color: var(--accent);
}

.bullet-list {
  display: grid;
  gap: 10px;
}

.bullet-list.compact { gap: 8px; }

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
}

@media (max-width: 1120px) {
  .page-shell {
    grid-template-columns: 1fr;
    width: min(100%, calc(100vw - 24px));
  }

  .rail-card {
    position: static;
  }

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

  .hero-grid,
  .two-col,
  .demo-layout,
  .demo-layout.compact,
  .architecture-grid,
  .results-grid,
  .math-grid,
  .three-up {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 720px) {
  .page-shell {
    width: calc(100vw - 12px);
    padding-top: 68px;
  }

  .panel,
  .hero {
    padding: 22px;
  }

  .theme-toggle {
    top: 10px;
    right: 10px;
  }

  .toc {
    grid-template-columns: 1fr;
  }

  .stats-grid,
  .control-row,
  .value-grid {
    grid-template-columns: 1fr;
  }

  .stack-visual {
    grid-template-columns: 1fr;
  }

  .stack-arrow {
    transform: rotate(90deg);
    min-height: 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-reveal] { opacity: 1; transform: none; }
}