@import url("https://fonts.googleapis.com/css2?family=Archivo+Black&family=IBM+Plex+Sans:wght@400;500;600&family=Space+Mono:wght@400;700&display=swap");

:root {
  --ink: #071a26;
  --ink-2: #0d2938;
  --ink-3: #15394a;
  --paper: #f4f1e8;
  --white: #fffdf5;
  --cyan: #52e5c4;
  --cyan-deep: #0d8d7c;
  --amber: #ffcb57;
  --red: #f05d5e;
  --blue: #45a7d8;
  --muted: #9bb4bd;
  --line: rgba(255, 255, 255, 0.15);
  --paper-line: rgba(7, 26, 38, 0.16);
  --display: "Archivo Black", "Arial Black", sans-serif;
  --body: "IBM Plex Sans", "Segoe UI", sans-serif;
  --mono: "Space Mono", "Courier New", monospace;
  --max: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 176px;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 17px;
  line-height: 1.62;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

code {
  font-family: var(--mono);
  font-size: 0.9em;
}

.chapter-copy code,
.chapter-note code,
.sci-figure code,
.imitation-steps code,
.imitation-grid code,
.result-notes code,
.section-head code {
  color: var(--cyan-deep);
}

.section-dark code,
.hero code {
  color: var(--cyan);
}

.code-block,
.code-block code {
  color: #cce2df;
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
  background: transparent;
}

:focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 8px 12px;
  background: var(--amber);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 700;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  z-index: 40;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgba(7, 26, 38, 0.94);
  color: var(--white);
  backdrop-filter: blur(12px);
}

.nav-shell {
  display: flex;
  min-height: 68px;
  width: min(calc(100% - 36px), var(--max));
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border: 1px solid var(--cyan);
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 700;
}

.brand-copy {
  display: grid;
  line-height: 1.1;
}

.brand-copy strong {
  font-family: var(--mono);
  font-size: 0.76rem;
  letter-spacing: 0.04em;
}

.brand-copy span {
  color: var(--muted);
  font-size: 0.69rem;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 22px;
  min-width: 0;
}

.site-tabs {
  display: flex;
  align-items: stretch;
  gap: 0;
  border: 1px solid var(--line);
}

.site-tab {
  margin: 0;
  padding: 8px 14px;
  border: 0;
  border-right: 1px solid var(--line);
  background: transparent;
  color: #dbe7e8;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.site-tab:last-child {
  border-right: 0;
}

.site-tab:hover {
  color: var(--cyan);
}

.site-tab.is-active {
  background: var(--cyan);
  color: var(--ink);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

html[data-tab="play"] .site-nav {
  display: none;
}

html[data-tab="play"] .site-footer {
  display: none;
}

html[data-tab="play"],
html[data-tab="play"] body {
  height: 100%;
  overflow: hidden;
  background: #071018;
}

.app-panel {
  height: calc(100dvh - 68px);
  background: #071018;
}

.app-panel iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  background: #071018;
}

.site-nav a {
  color: #dbe7e8;
  font-family: var(--mono);
  font-size: 0.68rem;
  text-decoration: none;
  text-transform: uppercase;
}

.site-nav a:hover {
  color: var(--cyan);
}

.nav-download {
  padding: 7px 11px;
  border: 1px solid var(--cyan);
  color: #dbe7e8;
  font-family: var(--mono);
  font-size: 0.68rem;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.nav-download:hover {
  color: var(--cyan);
}

.hero {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(rgba(82, 229, 196, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(82, 229, 196, 0.04) 1px, transparent 1px),
    var(--ink);
  background-size: 44px 44px;
  color: var(--white);
}

.hero::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  border-left: 2px dashed rgba(82, 229, 196, 0.11);
  content: "";
}

.hero-shell {
  position: relative;
  display: grid;
  min-height: 690px;
  width: min(calc(100% - 36px), var(--max));
  margin: 0 auto;
  padding: 92px 0 76px;
  align-items: center;
  grid-template-columns: minmax(0, 0.9fr) minmax(420px, 1.1fr);
  gap: clamp(38px, 6vw, 84px);
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.73rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.hero .eyebrow,
.section-dark .eyebrow {
  color: var(--cyan);
}

.hero h1 {
  max-width: 680px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(3.2rem, 7.1vw, 6.65rem);
  font-weight: 400;
  letter-spacing: -0.055em;
  line-height: 0.91;
  text-wrap: balance;
}

.hero h1 span {
  color: var(--amber);
}

.hero-lede {
  max-width: 600px;
  margin: 28px 0 0;
  color: #c8d7da;
  font-size: clamp(1rem, 1.6vw, 1.18rem);
}

.hero-actions {
  display: flex;
  margin-top: 32px;
  flex-wrap: wrap;
  gap: 12px;
}

.button {
  display: inline-flex;
  min-height: 44px;
  padding: 10px 16px;
  align-items: center;
  justify-content: center;
  border: 1px solid currentColor;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-decoration: none;
  text-transform: uppercase;
  transition: transform 150ms ease, background 150ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  border-color: var(--cyan);
  background: var(--cyan);
  color: var(--ink);
}

.button-secondary {
  border-color: var(--ink);
  background: var(--white);
  color: var(--ink);
}

.hero .button-secondary,
.section-dark .button-secondary {
  border-color: rgba(232, 240, 244, 0.72);
  background: rgba(255, 255, 255, 0.08);
  color: var(--white);
}

.hero-visual {
  position: relative;
  padding: 12px;
  border: 1px solid rgba(82, 229, 196, 0.35);
  background: var(--ink-2);
}

.hero-visual::before,
.hero-visual::after {
  position: absolute;
  width: 18px;
  height: 18px;
  border-color: var(--amber);
  content: "";
}

.hero-visual::before {
  top: -1px;
  left: -1px;
  border-top: 3px solid var(--amber);
  border-left: 3px solid var(--amber);
}

.hero-visual::after {
  right: -1px;
  bottom: -1px;
  border-right: 3px solid var(--amber);
  border-bottom: 3px solid var(--amber);
}

.hero-visual img {
  width: 100%;
}

.scope-caption {
  display: flex;
  padding: 10px 4px 0;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.63rem;
  text-transform: uppercase;
}

.scope-live {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--cyan);
}

.scope-live::before {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cyan);
  content: "";
  animation: pulse 1.5s ease-in-out infinite;
}

.metric-rack {
  display: grid;
  border-top: 1px solid var(--line);
  background: #081f2c;
  color: var(--white);
  grid-template-columns: repeat(4, 1fr);
}

.metric-rack > div {
  min-height: 128px;
  padding: 24px clamp(18px, 4vw, 48px);
  border-right: 1px solid var(--line);
}

.metric-rack > div:last-child {
  border-right: 0;
}

.metric-rack strong {
  display: block;
  color: var(--amber);
  font-family: var(--display);
  font-size: clamp(1.7rem, 3vw, 2.5rem);
  font-weight: 400;
  letter-spacing: -0.04em;
  line-height: 1;
}

.metric-rack span {
  display: block;
  margin-top: 9px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.66rem;
  line-height: 1.45;
  text-transform: uppercase;
}

.section {
  padding: clamp(76px, 10vw, 132px) 0;
}

.section-dark {
  background: var(--ink);
  color: var(--white);
}

.section-shell {
  width: min(calc(100% - 36px), var(--max));
  margin: 0 auto;
}

.section-head {
  display: grid;
  margin-bottom: 48px;
  grid-template-columns: minmax(0, 0.8fr) minmax(280px, 0.45fr);
  gap: clamp(32px, 8vw, 100px);
}

.section-head h2 {
  max-width: 780px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2.35rem, 5.5vw, 5rem);
  font-weight: 400;
  letter-spacing: -0.05em;
  line-height: 0.98;
  text-wrap: balance;
}

.section-head p {
  margin: 8px 0 0;
  color: #465b64;
}

.section-dark .section-head p {
  color: #dbe7e8;
}

.section-dark .section-head a {
  color: var(--cyan);
}

.court-rule {
  display: flex;
  margin: 34px 0;
  align-items: center;
  gap: 12px;
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.court-rule::before,
.court-rule::after {
  height: 1px;
  background: currentColor;
  content: "";
}

.court-rule::before {
  width: 24px;
}

.court-rule::after {
  flex: 1;
  opacity: 0.35;
}

.level-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(12, 1fr);
}

.level-card {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--paper-line);
  background: var(--white);
}

.level-card:nth-child(1),
.level-card:nth-child(2) {
  grid-column: span 6;
}

.level-card:nth-child(n + 3) {
  grid-column: span 4;
}

.level-media {
  position: relative;
  overflow: hidden;
  background: var(--ink);
}

.level-media img {
  width: 100%;
  transition: transform 300ms ease;
}

.level-card:hover .level-media img {
  transform: scale(1.018);
}

.level-index {
  position: absolute;
  z-index: 2;
  top: 12px;
  right: 12px;
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border: 1px solid var(--cyan);
  background: rgba(7, 26, 38, 0.88);
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 700;
}

.level-copy {
  padding: 24px;
}

.level-meta {
  display: flex;
  margin-bottom: 10px;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  padding: 3px 7px;
  border: 1px solid var(--paper-line);
  color: #4d626b;
  font-family: var(--mono);
  font-size: 0.58rem;
  text-transform: uppercase;
}

.level-copy h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.38rem;
  font-weight: 400;
  letter-spacing: -0.03em;
}

.level-copy p {
  margin: 10px 0 0;
  color: #50636b;
  font-size: 0.93rem;
  line-height: 1.55;
}

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

.method-card {
  border-top: 3px solid var(--cyan);
  background: var(--ink-2);
}

.method-card:nth-child(2) {
  border-color: var(--amber);
}

.method-card:nth-child(3) {
  border-color: var(--blue);
}

.method-card img {
  width: 100%;
}

.method-copy {
  padding: 24px;
}

.method-copy h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.35rem;
  font-weight: 400;
  letter-spacing: -0.03em;
}

.method-copy p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.formula-strip {
  display: grid;
  margin-top: 18px;
  border: 1px solid var(--paper-line);
  background: var(--white);
  grid-template-columns: repeat(4, 1fr);
}

.formula {
  min-height: 170px;
  padding: 24px;
  border-right: 1px solid var(--paper-line);
}

.formula:last-child {
  border-right: 0;
}

.algo-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 8px 0 28px;
}

.algo-jump a {
  padding: 6px 10px;
  border: 1px solid var(--paper-line);
  background: var(--white);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  text-transform: uppercase;
}

.algo-jump a:hover {
  border-color: var(--cyan-deep);
  color: var(--cyan-deep);
}

.algo-block {
  margin-bottom: 18px;
  padding: 28px 30px;
  border: 1px solid var(--paper-line);
  background: var(--white);
}

.algo-block header {
  display: grid;
  margin-bottom: 16px;
  grid-template-columns: 42px 1fr;
  gap: 14px;
  align-items: start;
}

.algo-block header span {
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 700;
  line-height: 1.4;
}

.algo-block header h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.35rem;
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.algo-block header p {
  margin: 6px 0 0;
  color: #5c6f77;
  font-size: 0.88rem;
}

.algo-block ol {
  margin: 0;
  padding-left: 1.2em;
}

.algo-block li {
  margin: 0 0 10px;
  padding-left: 0.35em;
  color: #33444c;
  line-height: 1.55;
}

.algo-block li:last-child {
  margin-bottom: 0;
}

.algo-block li ul {
  margin: 8px 0 0;
  padding-left: 1.1em;
}

.algo-block code {
  font-family: var(--mono);
  font-size: 0.82em;
}

.algo-use {
  margin: 18px 0 0;
  padding: 12px 14px;
  border-left: 3px solid var(--cyan-deep);
  background: #eef6f4;
  color: #2c3d44;
  font-size: 0.92rem;
  line-height: 1.55;
}

.algo-use strong {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.formula span {
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.62rem;
  text-transform: uppercase;
}

.formula h3 {
  margin: 8px 0 12px;
  font-family: var(--display);
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--ink);
}

.formula code {
  color: #1b3140;
  font-family: var(--mono);
  font-size: 0.73rem;
  line-height: 1.65;
}

.section-dark .formula-strip,
.section-dark .formula {
  border-color: var(--line);
}

.section-dark .formula-strip {
  background: var(--ink-2);
}

.section-dark .formula span {
  color: var(--cyan);
}

.section-dark .formula h3 {
  color: var(--white);
}

.section-dark .formula code {
  color: #dbe7e8;
}

.scoring-layout {
  display: grid;
  align-items: start;
  grid-template-columns: minmax(0, 0.8fr) minmax(460px, 1.2fr);
  gap: clamp(40px, 8vw, 100px);
}

.reward-list {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.reward-list li {
  display: grid;
  padding: 11px 0;
  border-bottom: 1px solid var(--paper-line);
  grid-template-columns: 1fr auto;
  gap: 16px;
}

.reward-list code {
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.8rem;
  font-weight: 700;
}

.ledger {
  border: 1px solid var(--paper-line);
  background: var(--white);
}

.ledger-display {
  display: grid;
  background: var(--ink);
  color: var(--white);
  grid-template-columns: 1fr 1fr;
}

.player-score {
  padding: 24px;
}

.player-score + .player-score {
  border-left: 1px solid var(--line);
}

.player-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.62rem;
  text-transform: uppercase;
}

.player-label i {
  width: 9px;
  height: 22px;
  border: 2px solid var(--cyan);
  background: transparent;
}

.player-score:last-child .player-label i {
  border-color: var(--red);
}

.score-value {
  margin-top: 10px;
  font-family: var(--display);
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  letter-spacing: -0.05em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.score-sub {
  margin-top: 8px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.62rem;
}

.ledger-controls {
  padding: 24px;
}

.side-switch {
  display: grid;
  margin: 0 0 18px;
  border: 1px solid var(--paper-line);
  grid-template-columns: 1fr 1fr;
}

.side-switch button {
  padding: 8px 12px;
  border: 0;
  background: transparent;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.66rem;
  font-weight: 700;
  text-transform: uppercase;
}

.side-switch button[aria-pressed="true"] {
  background: var(--ink);
  color: var(--cyan);
}

.event-buttons {
  display: grid;
  gap: 8px;
  grid-template-columns: repeat(2, 1fr);
}

.event-button {
  min-height: 54px;
  padding: 9px 12px;
  border: 1px solid var(--paper-line);
  background: var(--paper);
  cursor: pointer;
  text-align: left;
}

.event-button:hover {
  border-color: var(--cyan-deep);
}

.event-button strong,
.event-button small {
  display: block;
}

.event-button strong {
  font-family: var(--mono);
  font-size: 0.71rem;
}

.event-button small {
  margin-top: 3px;
  color: #61747b;
  font-size: 0.67rem;
}

.ledger-actions {
  display: flex;
  margin-top: 14px;
  gap: 8px;
}

.ledger-action {
  padding: 8px 11px;
  border: 1px solid var(--paper-line);
  background: transparent;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.62rem;
  text-transform: uppercase;
}

.ledger-action:hover {
  background: var(--ink);
  color: var(--white);
}

.ledger-status {
  min-height: 40px;
  margin: 18px 0 0;
  padding: 9px 11px;
  border-left: 3px solid var(--amber);
  background: #f7edd1;
  font-family: var(--mono);
  font-size: 0.7rem;
}

.event-log {
  margin: 0;
  padding: 0 24px 22px;
  list-style: none;
}

.event-log li {
  display: flex;
  padding: 6px 0;
  justify-content: space-between;
  border-top: 1px solid var(--paper-line);
  color: #566a72;
  font-family: var(--mono);
  font-size: 0.62rem;
}

.results-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 0.62fr);
  gap: 48px;
}

.result-list {
  display: grid;
  gap: 18px;
}

.result-row {
  display: grid;
  align-items: center;
  grid-template-columns: 150px 1fr 58px;
  gap: 14px;
}

.result-label,
.result-value {
  font-family: var(--mono);
  font-size: 0.68rem;
}

.result-value {
  color: var(--cyan);
  font-weight: 700;
  text-align: right;
}

.bar-track {
  height: 11px;
  background: var(--ink-3);
}

.bar-fill {
  width: var(--value);
  height: 100%;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 900ms cubic-bezier(0.2, 0.75, 0.25, 1);
}

.is-visible .bar-fill {
  transform: scaleX(1);
}

.result-row.is-weak .bar-fill {
  background: var(--amber);
}

.result-notes {
  padding: 28px;
  border: 1px solid var(--line);
}

.result-notes h3 {
  margin: 0 0 18px;
  font-family: var(--display);
  font-size: 1.35rem;
  font-weight: 400;
}

.result-notes dl {
  margin: 0;
}

.result-notes div {
  display: grid;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  grid-template-columns: 1fr auto;
  gap: 16px;
}

.result-notes dt {
  color: var(--muted);
}

.result-notes dd {
  margin: 0;
  color: var(--amber);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 700;
  text-align: right;
}

.architecture {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  align-items: stretch;
}

.architecture-step {
  min-height: 150px;
  padding: 20px;
  border: 1px solid var(--paper-line);
  background: var(--white);
}

.architecture-step span {
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.6rem;
  font-weight: 700;
}

.architecture-step strong {
  display: block;
  margin-top: 8px;
  font-family: var(--display);
  font-size: 1.05rem;
  font-weight: 400;
  line-height: 1.2;
}

.architecture-step p {
  margin: 10px 0 0;
  color: #5c6f77;
  font-size: 0.8rem;
  line-height: 1.45;
}

.architecture-arrow {
  display: grid;
  width: 38px;
  place-items: center;
  color: var(--cyan-deep);
  font-family: var(--mono);
}

.code-panel {
  display: grid;
  margin-top: 38px;
  overflow: hidden;
  background: var(--ink);
  color: var(--white);
  grid-template-columns: 0.78fr 1.22fr;
}

.code-copy {
  padding: 36px;
}

.code-copy h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.7rem;
  font-weight: 400;
  letter-spacing: -0.03em;
}

.code-copy p {
  color: var(--muted);
  font-size: 0.92rem;
}

.code-block {
  margin: 0;
  padding: 36px;
  overflow-x: auto;
  border-left: 1px solid var(--line);
  background: #06151f;
  color: #cce2df;
  font-family: var(--mono);
  font-size: 0.72rem;
  line-height: 1.8;
}

.code-block .accent {
  color: var(--amber);
}

.deliverables {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(4, 1fr);
}

.deliverable {
  min-height: 190px;
  padding: 22px;
  border: 1px solid var(--paper-line);
  color: inherit;
  text-decoration: none;
  transition: border-color 150ms ease, transform 150ms ease;
}

.deliverable:hover {
  border-color: var(--cyan-deep);
  transform: translateY(-3px);
}

.deliverable span {
  color: var(--cyan-deep);
  font-family: var(--mono);
  font-size: 0.6rem;
  font-weight: 700;
  text-transform: uppercase;
}

.deliverable h3 {
  margin: 24px 0 8px;
  font-family: var(--display);
  font-size: 1.25rem;
  font-weight: 400;
}

.deliverable p {
  margin: 0;
  color: #5a6d75;
  font-size: 0.82rem;
}

.site-footer {
  padding: 48px 0;
  background: var(--ink);
  color: var(--white);
}

.footer-shell {
  display: grid;
  width: min(calc(100% - 36px), var(--max));
  margin: 0 auto;
  align-items: end;
  grid-template-columns: 1fr auto;
  gap: 32px;
}

.footer-title {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(1.8rem, 4vw, 3.5rem);
  font-weight: 400;
  letter-spacing: -0.045em;
  line-height: 1;
}

.footer-meta {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.62rem;
  text-align: right;
  text-transform: uppercase;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 550ms ease, transform 550ms ease;
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@keyframes pulse {
  0%,
  100% {
    opacity: 0.35;
    transform: scale(0.75);
  }
  50% {
    opacity: 1;
    transform: scale(1);
  }
}

@media (max-width: 980px) {
  .site-nav {
    display: none;
  }

  .site-tabs {
    flex: 1;
  }

  .site-tab {
    flex: 1;
    padding: 8px 8px;
    font-size: 0.62rem;
    text-align: center;
  }

  .hero-shell {
    min-height: auto;
    grid-template-columns: 1fr;
  }

  .hero-copy {
    max-width: 760px;
  }

  .hero-visual {
    max-width: 720px;
  }

  .metric-rack {
    grid-template-columns: repeat(2, 1fr);
  }

  .metric-rack > div:nth-child(2) {
    border-right: 0;
  }

  .metric-rack > div:nth-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }

  .level-card:nth-child(n) {
    grid-column: span 6;
  }

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

  .method-card {
    display: grid;
    grid-template-columns: 0.9fr 1.1fr;
  }

  .scoring-layout,
  .results-layout {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .nav-shell {
    width: min(calc(100% - 24px), var(--max));
  }

  .brand-copy span {
    display: none;
  }

  .nav-download {
    padding: 7px 8px;
    font-size: 0.58rem !important;
  }

  .hero-shell,
  .section-shell,
  .footer-shell {
    width: min(calc(100% - 24px), var(--max));
  }

  .hero-shell {
    padding: 72px 0 54px;
  }

  .hero h1 {
    font-size: clamp(3rem, 16vw, 5.1rem);
  }

  .section {
    padding: 72px 0;
  }

  .section-head {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .level-card:nth-child(n) {
    grid-column: span 12;
  }

  .method-card {
    display: block;
  }

  .algo-block {
    padding: 22px 18px;
  }

  .algo-block header {
    grid-template-columns: 1fr;
    gap: 4px;
  }

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

  .formula {
    border-right: 0;
    border-bottom: 1px solid var(--paper-line);
  }

  .section-dark .formula {
    border-bottom-color: var(--line);
  }

  .formula:last-child {
    border-bottom: 0;
  }

  .scoring-layout {
    grid-template-columns: 1fr;
  }

  .event-buttons {
    grid-template-columns: 1fr;
  }

  .result-row {
    grid-template-columns: 106px 1fr 48px;
  }

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

  .architecture-arrow {
    width: auto;
    height: 34px;
    transform: rotate(90deg);
  }

  .code-panel {
    grid-template-columns: 1fr;
  }

  .code-block {
    padding: 24px;
    border-top: 1px solid var(--line);
    border-left: 0;
  }

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

  .footer-shell {
    grid-template-columns: 1fr;
  }

  .footer-meta {
    text-align: left;
  }
}

html[data-tab="play"] .talk-rail {
  display: none;
}

.talk-rail {
  position: sticky;
  top: 68px;
  z-index: 15;
  display: flex;
  overflow-x: auto;
  gap: 0;
  padding: 0 18px;
  border-bottom: 1px solid var(--paper-line);
  background: var(--paper);
}

.talk-rail a {
  flex: 1 0 auto;
  padding: 12px 16px;
  color: #3d5366;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-align: center;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.talk-rail a span {
  display: block;
  margin-bottom: 2px;
  color: var(--cyan-deep);
}

.talk-rail a.is-active {
  color: var(--ink);
  background: var(--white);
  box-shadow: inset 0 -3px 0 var(--cyan-deep);
}

.chapter-shell {
  display: grid;
  align-items: start;
  grid-template-columns: minmax(0, 1.05fr) minmax(280px, 0.95fr);
  gap: 40px;
}

.chapter-copy h2 {
  margin: 0 0 16px;
  font-family: var(--display);
  font-size: clamp(2rem, 4.4vw, 3.4rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1.05;
  color: var(--ink);
}

.chapter-copy p,
.chapter-copy li {
  color: #1b3140;
}

.chapter-note {
  margin: 18px 0 0;
  padding: 14px 16px;
  border-left: 3px solid var(--cyan-deep);
  background: var(--white);
  color: #1b3140;
}

.section-dark .chapter-copy h2,
.section-dark .chapter-copy p,
.section-dark .chapter-copy li {
  color: #e8f0f2;
}

.section-dark .chapter-note {
  background: var(--ink-2);
  color: #e8f0f2;
  border-left-color: var(--cyan);
}

.state-list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.state-list li {
  display: grid;
  grid-template-columns: 7.5rem 1fr;
  gap: 12px;
  padding: 8px 0;
  border-top: 1px solid var(--paper-line);
  font-size: 0.95rem;
}

.section-dark .state-list li {
  border-top-color: var(--line);
}

.formula-stack {
  display: grid;
  gap: 8px;
  margin: 20px 0;
}

.formula-stack .formula {
  min-height: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-right: 1px solid var(--line);
}

.formula-stack .formula.is-active {
  border-color: var(--cyan);
  background: rgba(82, 229, 196, 0.1);
}

.demo-stage {
  padding: 16px;
  border: 1px solid var(--line);
  background: #071018;
}

.demo-stage canvas {
  display: block;
  width: 100%;
  height: auto;
  background: #102033;
}

.state-tuple {
  margin: 12px 0 0;
  padding: 10px 12px;
  overflow-x: auto;
  background: #0d1c28;
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 0.78rem;
}

.action-chips,
.stat-row,
.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.action-chips button {
  min-width: 72px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  background: transparent;
  color: #e8f0f2;
  font-family: var(--mono);
  font-size: 0.72rem;
}

.action-chips button.is-active {
  border-color: var(--cyan);
  background: var(--cyan);
  color: var(--ink);
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
}

.stat-row div {
  padding: 8px 10px;
  background: #0d1c28;
}

.stat-row span {
  display: block;
  color: #9bb4bd;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.stat-row strong {
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 0.9rem;
}

.controls label {
  display: grid;
  gap: 4px;
  color: inherit;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.controls input[type="range"],
.controls select {
  min-width: 140px;
  accent-color: var(--cyan-deep);
}

.section-dark .controls select {
  border: 1px solid var(--line);
  background: var(--ink-2);
  color: var(--white);
}

.section-dark .controls input[type="range"] {
  accent-color: var(--cyan);
}

@media (max-width: 920px) {
  .chapter-shell,
  .stat-row {
    grid-template-columns: 1fr;
  }
}

.imitation-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  margin: 8px 0 36px;
}

.imitation-grid article {
  padding: 28px;
  border: 1px solid var(--paper-line);
  background: var(--white);
}

.imitation-grid h3,
.imitation-steps h3 {
  margin: 6px 0 12px;
  font-family: var(--display);
  font-size: 1.45rem;
  font-weight: 400;
  letter-spacing: 0.01em;
}

.imitation-grid p,
.imitation-steps p {
  margin: 0;
  color: #3d5366;
}

.imitation-formulas {
  margin-bottom: 40px;
}

.imitation-steps {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 48px;
}

.imitation-steps article {
  padding: 22px 20px 24px;
  border-top: 3px solid var(--cyan);
  background: var(--white);
}

.imitation-steps span {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--cyan-deep);
  letter-spacing: 0.08em;
}

.sci-figure {
  margin: 0 0 48px;
  overflow-x: auto;
}

.sci-figure figcaption {
  margin: 0 0 16px;
  max-width: 72ch;
  font-size: 0.95rem;
  line-height: 1.55;
}

.sci-figure figcaption strong {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--cyan-deep);
}

.section-dark .sci-figure figcaption strong,
.sci-figure.on-dark figcaption strong {
  color: var(--cyan);
}

.section-dark .sci-figure figcaption,
.sci-figure.on-dark figcaption {
  color: #dbe7e8;
}

.chart-svg {
  display: block;
  width: 100%;
  height: auto;
  background: #071018;
  border: 1px solid var(--line);
}

.section:not(.section-dark) .chart-svg {
  background: var(--ink);
}

.chart-bg {
  fill: rgba(255, 255, 255, 0.03);
}

.phase-bc {
  fill: rgba(255, 203, 87, 0.08);
}

.phase-dagger {
  fill: rgba(69, 167, 216, 0.1);
}

.phase-rl {
  fill: rgba(82, 229, 196, 0.08);
}

.phase-label {
  fill: #d5e4e7;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.grid-y line {
  stroke: rgba(255, 255, 255, 0.12);
  stroke-width: 1;
}

.tick {
  fill: #d5e4e7;
  font-family: var(--mono);
  font-size: 11px;
}

.tick.muted {
  fill: #52e5c4;
  font-size: 10px;
}

.axis-title {
  fill: #f4f1e8;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.series-line {
  fill: none;
  stroke: #52e5c4;
  stroke-width: 2.25;
  stroke-linejoin: round;
  stroke-linecap: round;
}

.series-line.series-amber {
  stroke: #ffcb57;
}

.bar-pred {
  fill: #52e5c4;
}

.bar-pred.is-amber {
  fill: #ffcb57;
}

.bar-imit {
  fill: #45a7d8;
}

.bar-resid {
  fill: #ffcb57;
}

.bar-feat {
  fill: #f05d5e;
}

.error-bar {
  stroke: #f4f1e8;
  stroke-width: 1.5;
}

.chart-source {
  margin: 10px 0 0;
  color: #9bb4bd;
  font-family: var(--mono);
  font-size: 0.68rem;
  line-height: 1.5;
}

.section:not(.section-dark) .chart-source {
  color: #3d5366;
}

.lab-frame-wrap {
  margin-top: 8px;
  border: 1px solid var(--paper-line);
  background: #071a26;
}

.lab-frame-wrap iframe {
  display: block;
  width: 100%;
  min-height: 1200px;
  height: 1200px;
  border: 0;
  background: #071a26;
}

.result-notes {
  margin-top: 8px;
}

@media (max-width: 920px) {
  .imitation-grid,
  .imitation-steps {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}