:root {
  --ink: #151711;
  --ink-soft: #272a21;
  --paper: #f2efe4;
  --paper-bright: #fbf9f2;
  --paper-deep: #ddd7c6;
  --signal: #dfff45;
  --signal-dark: #b8d92c;
  --vermillion: #e75a35;
  --muted: #716f64;
  --line: rgba(21, 23, 17, 0.17);
  --line-light: rgba(255, 255, 255, 0.14);
  --display: "Newsreader", "Iowan Old Style", Baskerville, Georgia, serif;
  --sans: "Plus Jakarta Sans", "Avenir Next", Helvetica, sans-serif;
  --mono: "DM Mono", "IBM Plex Mono", monospace;
  --content: 1180px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(255, 255, 255, 0.82), transparent 26rem),
    var(--paper);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
}

body::selection {
  color: var(--ink);
  background: var(--signal);
}

.top-anchor {
  position: absolute;
  top: 0;
  left: 0;
  width: 1px;
  height: 1px;
  pointer-events: none;
}

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

button,
input {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
}

p,
h1,
h2,
h3,
h4,
dl,
dd,
blockquote {
  margin-top: 0;
}

code {
  padding: 0.08em 0.35em;
  border: 1px solid rgba(21, 23, 17, 0.12);
  border-radius: 0.25rem;
  background: rgba(21, 23, 17, 0.045);
  font-family: var(--mono);
  font-size: 0.84em;
}

.dark-section code,
.site-footer code {
  border-color: rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.07);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 1000;
  padding: 0.7rem 1rem;
  color: var(--ink);
  background: var(--signal);
  font-family: var(--mono);
  font-size: 0.75rem;
  text-decoration: none;
  transform: translateY(-160%);
  transition: transform 180ms ease;
}

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

:focus-visible {
  outline: 2px solid var(--vermillion);
  outline-offset: 4px;
}

.dark-section :focus-visible,
.site-footer :focus-visible {
  outline-color: var(--signal);
}

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
  padding: 0 3.5vw;
  color: var(--paper-bright);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(21, 23, 17, 0.78);
  backdrop-filter: blur(16px);
  transition: height 300ms var(--ease), background 300ms ease;
}

.site-header.is-compact {
  height: 64px;
  background: rgba(21, 23, 17, 0.94);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.72rem;
  min-width: 11.5rem;
  text-decoration: none;
}

.brand > span:last-child {
  display: grid;
  line-height: 1.05;
}

.brand strong {
  font-family: var(--mono);
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.14em;
}

.brand small {
  margin-top: 0.3rem;
  color: rgba(255, 255, 255, 0.55);
  font-size: 0.66rem;
}

.brand-mark {
  position: relative;
  display: inline-block;
  width: 30px;
  height: 30px;
  flex: 0 0 auto;
}

.brand-stone {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
}

.brand-stone--black {
  top: 1px;
  left: 1px;
  background: #050605;
  border: 1px solid rgba(255, 255, 255, 0.22);
}

.brand-stone--white {
  right: 1px;
  bottom: 1px;
  background: var(--paper-bright);
  border: 1px solid rgba(21, 23, 17, 0.28);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: clamp(1.25rem, 2.5vw, 2.5rem);
}

.header-nav a {
  position: relative;
  color: rgba(255, 255, 255, 0.74);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
  transition: color 200ms ease;
}

.header-nav a::after {
  position: absolute;
  right: 0;
  bottom: -0.5rem;
  left: 0;
  height: 1px;
  background: var(--signal);
  content: "";
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 300ms var(--ease);
}

.header-nav a:hover {
  color: white;
}

.header-nav a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 11px 9px;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.menu-button span:not(.sr-only) {
  display: block;
  width: 100%;
  height: 1px;
  margin: 6px 0;
  background: white;
  transition: transform 250ms ease;
}

.mobile-nav {
  position: fixed;
  inset: 76px 0 auto;
  z-index: 90;
  padding: 1rem 5vw 1.5rem;
  color: var(--paper-bright);
  background: rgba(21, 23, 17, 0.98);
  border-bottom: 1px solid var(--line-light);
}

.mobile-nav a {
  display: block;
  padding: 0.8rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  font-family: var(--mono);
  font-size: 0.76rem;
  text-decoration: none;
}

.chapter-rail {
  position: fixed;
  top: 50%;
  left: 1.15rem;
  z-index: 50;
  display: grid;
  grid-template-columns: 10px auto;
  column-gap: 0.65rem;
  color: rgba(255, 255, 255, 0.5);
  mix-blend-mode: difference;
  transform: translateY(-44%);
}

.rail-label {
  position: absolute;
  top: -4rem;
  left: -0.05rem;
  font-family: var(--mono);
  font-size: 0.54rem;
  letter-spacing: 0.14em;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
}

.rail-track {
  position: relative;
  width: 1px;
  height: 214px;
  margin: 0.45rem auto;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.22);
}

.rail-track span {
  position: absolute;
  inset: 0 0 auto;
  height: 0;
  background: white;
  transition: height 120ms linear;
}

.chapter-rail ol {
  display: grid;
  gap: 0.2rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.chapter-rail a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  min-height: 24px;
  font-family: var(--mono);
  font-size: 0.56rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  opacity: 0.55;
  transition: opacity 180ms ease, transform 180ms ease;
}

.chapter-rail a span {
  width: 1.25rem;
}

.chapter-rail a.is-active {
  opacity: 1;
  transform: translateX(3px);
}

.dark-section {
  position: relative;
  color: var(--paper-bright);
  background:
    radial-gradient(circle at 12% 5%, rgba(223, 255, 69, 0.07), transparent 24rem),
    radial-gradient(circle at 90% 75%, rgba(231, 90, 53, 0.07), transparent 30rem),
    var(--ink);
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(420px, 0.92fr);
  align-items: center;
  min-height: 100svh;
  padding: 128px max(6vw, 72px) 90px max(9vw, 110px);
  overflow: hidden;
}

.hero::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 53%;
  width: 1px;
  background: rgba(255, 255, 255, 0.08);
  content: "";
}

.hero-grain,
.hero-grain::before {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero-grain {
  background-image: linear-gradient(rgba(255, 255, 255, 0.016) 1px, transparent 1px);
  background-size: 100% 4px;
  opacity: 0.5;
}

.hero-grain::before {
  background: radial-gradient(circle at 74% 42%, rgba(223, 255, 69, 0.09), transparent 28rem);
  content: "";
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 790px;
  padding-right: 7vw;
}

.eyebrow,
.chapter-kicker,
.micro-label {
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 400;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  color: rgba(255, 255, 255, 0.52);
}

.eyebrow span {
  color: var(--signal);
}

.eyebrow::before {
  width: 2.25rem;
  height: 1px;
  background: var(--signal);
  content: "";
}

.hero h1 {
  max-width: 850px;
  margin: 1.25rem 0 1.5rem;
  font-family: var(--display);
  font-size: clamp(4.2rem, 7.5vw, 8.75rem);
  font-weight: 300;
  letter-spacing: -0.065em;
  line-height: 0.88;
}

.hero h1 em {
  color: var(--signal);
  font-weight: 300;
}

.hero-lede {
  max-width: 630px;
  margin-bottom: 2rem;
  color: rgba(255, 255, 255, 0.68);
  font-family: var(--display);
  font-size: clamp(1.25rem, 1.8vw, 1.7rem);
  line-height: 1.35;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-width: 240px;
  padding: 0.92rem 1.1rem;
  border: 1px solid transparent;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-decoration: none;
  text-transform: uppercase;
  transition: transform 250ms var(--ease), box-shadow 250ms ease;
}

.button--signal {
  color: var(--ink);
  background: var(--signal);
}

.button:hover {
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.22);
  transform: translateY(-3px);
}

.text-link {
  position: relative;
  color: rgba(255, 255, 255, 0.72);
  font-family: var(--mono);
  font-size: 0.71rem;
  text-decoration: none;
  text-transform: uppercase;
}

.text-link::after {
  position: absolute;
  right: 0;
  bottom: -0.4rem;
  left: 0;
  height: 1px;
  background: rgba(255, 255, 255, 0.32);
  content: "";
}

.hero-stats {
  display: flex;
  gap: clamp(1.6rem, 3vw, 3.5rem);
  margin: clamp(2.5rem, 5vh, 4.5rem) 0 0;
}

.hero-stats div {
  padding-left: 0.8rem;
  border-left: 1px solid rgba(255, 255, 255, 0.18);
}

.hero-stats dt {
  font-family: var(--display);
  font-size: clamp(1.6rem, 2.5vw, 2.5rem);
  letter-spacing: -0.04em;
  line-height: 1;
}

.hero-stats dd {
  margin-top: 0.35rem;
  color: rgba(255, 255, 255, 0.45);
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero-visual {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-width: 0;
}

.go-board {
  position: relative;
  aspect-ratio: 1;
  background-color: #c99f5b;
  background-image:
    linear-gradient(to right, transparent calc(50% - 0.5px), rgba(35, 24, 8, 0.55) 50%, transparent calc(50% + 0.5px)),
    linear-gradient(to bottom, transparent calc(50% - 0.5px), rgba(35, 24, 8, 0.55) 50%, transparent calc(50% + 0.5px));
  background-size: calc(100% / 18) calc(100% / 18);
  border: 1px solid rgba(255, 255, 255, 0.16);
  box-shadow: 0 45px 90px rgba(0, 0, 0, 0.46), inset 0 0 50px rgba(74, 39, 4, 0.1);
}

.hero-board {
  width: min(38vw, 560px);
  min-width: 410px;
}

.hero-board::after,
.value-board::after {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 25% 16%, rgba(255, 255, 255, 0.18), transparent 22%),
    linear-gradient(100deg, rgba(255, 255, 255, 0.03), rgba(71, 39, 7, 0.08));
  content: "";
  pointer-events: none;
}

.board-stone,
.stone {
  position: absolute;
  z-index: 2;
  width: calc(100% / 18 * 0.82);
  aspect-ratio: 1;
  border-radius: 50%;
  transform: translate(-50%, -50%);
}

.board-stone--black,
.stone--black {
  background: radial-gradient(circle at 34% 26%, #54564e 0, #161714 37%, #020302 86%);
  box-shadow: 3px 5px 7px rgba(0, 0, 0, 0.38);
}

.board-stone--white,
.stone--white {
  background: radial-gradient(circle at 34% 26%, #fff 0, #f3f0e8 42%, #b9b5aa 100%);
  box-shadow: 3px 5px 8px rgba(0, 0, 0, 0.28);
}

.policy-pulse {
  position: absolute;
  z-index: 5;
  width: 10%;
  aspect-ratio: 1;
  padding: 0;
  color: var(--ink);
  border: 0;
  border-radius: 50%;
  background: var(--signal);
  box-shadow: 0 0 0 8px rgba(223, 255, 69, 0.17), 0 0 36px rgba(223, 255, 69, 0.44);
  cursor: help;
  transform: translate(-50%, -50%);
  animation: policyPulse 2.8s ease-in-out infinite;
}

.policy-pulse span {
  font-family: var(--mono);
  font-size: clamp(0.45rem, 0.66vw, 0.62rem);
  font-weight: 500;
}

.policy-pulse--a { top: 33.35%; left: 66.65%; }
.policy-pulse--b { top: 61.1%; left: 38.9%; animation-delay: -0.9s; }
.policy-pulse--c { top: 77.8%; left: 77.8%; animation-delay: -1.8s; }

@keyframes policyPulse {
  0%, 100% { box-shadow: 0 0 0 7px rgba(223, 255, 69, 0.14), 0 0 30px rgba(223, 255, 69, 0.32); }
  50% { box-shadow: 0 0 0 15px rgba(223, 255, 69, 0.02), 0 0 50px rgba(223, 255, 69, 0.58); }
}

.search-thread {
  position: absolute;
  z-index: 4;
  width: 1px;
  height: 31%;
  background: linear-gradient(var(--signal), transparent);
  transform-origin: top;
  opacity: 0.68;
}

.search-thread--one { top: 35%; left: 67%; transform: rotate(43deg); }
.search-thread--two { top: 61%; left: 39%; height: 24%; transform: rotate(-52deg); }

.board-caption {
  display: grid;
  grid-template-columns: 34px minmax(0, 330px);
  gap: 0.7rem;
  align-items: start;
  width: min(38vw, 560px);
  color: rgba(255, 255, 255, 0.5);
  font-family: var(--mono);
  font-size: 0.62rem;
  line-height: 1.5;
}

.board-caption strong {
  color: rgba(255, 255, 255, 0.85);
  font-weight: 500;
}

.board-caption--top {
  justify-content: end;
  margin-bottom: 0.85rem;
  margin-left: 3rem;
}

.board-caption--bottom {
  margin-top: 0.9rem;
  margin-left: -3rem;
}

.caption-index {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  color: var(--signal);
  border: 1px solid rgba(223, 255, 69, 0.38);
}

.hero-footnote {
  position: absolute;
  bottom: 1.5rem;
  left: max(9vw, 110px);
  display: flex;
  align-items: center;
  gap: 0.55rem;
  color: rgba(255, 255, 255, 0.32);
  font-family: var(--mono);
  font-size: 0.58rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.pulse-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--signal);
  box-shadow: 0 0 0 5px rgba(223, 255, 69, 0.1);
}

.thesis-band {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 5vw;
  align-items: start;
  padding: clamp(4rem, 8vw, 8rem) max(8vw, 80px) clamp(4rem, 7vw, 7rem) max(11vw, 130px);
  border-bottom: 1px solid var(--line);
  background: var(--paper-bright);
}

.thesis-band > p {
  margin-top: 0.7rem;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.13em;
}

.thesis-band h2 {
  max-width: 1040px;
  margin-bottom: 0;
  font-family: var(--display);
  font-size: clamp(2.5rem, 5vw, 5.6rem);
  font-weight: 300;
  letter-spacing: -0.045em;
  line-height: 1.03;
}

.thesis-band h2 span {
  border-bottom: 0.1em solid var(--vermillion);
}

.chapter {
  position: relative;
  padding: clamp(7rem, 11vw, 11rem) max(8vw, 90px) clamp(7rem, 11vw, 11rem) max(11vw, 130px);
}

.chapter-heading {
  display: grid;
  grid-template-columns: minmax(280px, 0.86fr) minmax(320px, 0.64fr);
  column-gap: 8vw;
  align-items: end;
  max-width: var(--content);
  margin: 0 auto clamp(4rem, 8vw, 7.5rem);
}

.chapter-heading .chapter-kicker {
  grid-column: 1 / -1;
  margin-bottom: 1.5rem;
  color: var(--muted);
}

.chapter-kicker span {
  display: inline-grid;
  width: 2.2rem;
  height: 2.2rem;
  margin-right: 0.7rem;
  place-items: center;
  color: var(--ink);
  border: 1px solid var(--line);
}

.chapter-heading h2,
.glossary-heading h2 {
  margin-bottom: 0;
  font-family: var(--display);
  font-size: clamp(3.4rem, 6.4vw, 7rem);
  font-weight: 300;
  letter-spacing: -0.055em;
  line-height: 0.92;
}

.chapter-heading > p:last-child {
  max-width: 570px;
  margin-bottom: 0.25rem;
  color: var(--muted);
  font-family: var(--display);
  font-size: clamp(1.15rem, 1.55vw, 1.45rem);
  line-height: 1.45;
}

.chapter-heading--light .chapter-kicker,
.chapter-heading--light > p:last-child {
  color: rgba(255, 255, 255, 0.55);
}

.chapter-heading--light .chapter-kicker span {
  color: var(--signal);
  border-color: rgba(223, 255, 69, 0.34);
}

.branching-lab {
  display: grid;
  grid-template-columns: minmax(340px, 0.8fr) minmax(420px, 1.2fr);
  min-height: 560px;
  max-width: var(--content);
  margin: 0 auto;
  border: 1px solid var(--line);
  background: var(--paper-bright);
}

.branching-copy {
  padding: clamp(2.2rem, 4vw, 4rem);
  border-right: 1px solid var(--line);
}

.micro-label {
  color: var(--vermillion);
}

.branching-copy h3,
.contrast-note h3,
.selfplay-loop h3,
.correlation-story h3,
.puct-heading h3,
.leaf-mixer h3,
.machine-compare h3,
.understanding-check h3,
.glossary-heading h2 {
  font-family: var(--display);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1.05;
}

.branching-copy h3 {
  max-width: 400px;
  margin: 1rem 0 1.25rem;
  font-size: clamp(2.2rem, 3.5vw, 3.8rem);
}

.branching-copy > p:not(.micro-label) {
  max-width: 420px;
  color: var(--muted);
}

.branching-copy label {
  display: flex;
  justify-content: space-between;
  margin-top: 2.3rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.branching-copy output {
  color: var(--vermillion);
  font-weight: 500;
}

input[type="range"] {
  width: 100%;
  height: 8px;
  margin: 1.2rem 0;
  appearance: none;
  border: 0;
  border-radius: 999px;
  background: rgba(21, 23, 17, 0.25);
  cursor: ew-resize;
  touch-action: pan-y;
}

input[type="range"]::-webkit-slider-thumb {
  width: 17px;
  height: 17px;
  appearance: none;
  border: 3px solid var(--paper-bright);
  border-radius: 50%;
  background: var(--vermillion);
  box-shadow: 0 0 0 1px var(--vermillion);
}

input[type="range"]::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border: 3px solid var(--paper-bright);
  border-radius: 50%;
  background: var(--vermillion);
  box-shadow: 0 0 0 1px var(--vermillion);
}

.branch-readout {
  display: grid;
  margin-top: 1.8rem;
  padding-top: 1.8rem;
  border-top: 1px solid var(--line);
}

.branch-readout span,
.branch-readout small {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.branch-readout strong {
  max-width: 100%;
  margin: 0.45rem 0;
  overflow-wrap: anywhere;
  font-family: var(--display);
  font-size: clamp(2.1rem, 3.6vw, 4rem);
  font-weight: 400;
  letter-spacing: -0.04em;
  line-height: 1;
}

.branching-visual {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(90deg, rgba(21, 23, 17, 0.035) 1px, transparent 1px),
    linear-gradient(rgba(21, 23, 17, 0.035) 1px, transparent 1px),
    var(--paper);
  background-size: 28px 28px;
}

.tree-root {
  position: absolute;
  top: 11%;
  left: 50%;
  z-index: 3;
  display: grid;
  width: 52px;
  height: 52px;
  place-items: center;
  color: var(--paper-bright);
  border-radius: 50%;
  background: var(--ink);
  font-family: var(--display);
  font-size: 1.5rem;
  transform: translateX(-50%);
}

.tree-level {
  position: absolute;
  left: 50%;
  display: flex;
  justify-content: space-between;
  transform: translateX(-50%);
}

.tree-level::before {
  position: absolute;
  top: -70px;
  right: 10%;
  left: 10%;
  height: 72px;
  border-top: 1px solid rgba(21, 23, 17, 0.28);
  border-right: 1px solid rgba(21, 23, 17, 0.28);
  border-left: 1px solid rgba(21, 23, 17, 0.28);
  content: "";
  transform: perspective(200px) rotateX(-24deg);
  transform-origin: bottom;
}

.tree-level i {
  position: relative;
  z-index: 2;
  display: block;
  width: 18px;
  height: 18px;
  border: 1px solid var(--ink);
  border-radius: 50%;
  background: var(--paper-bright);
}

.tree-level i:nth-child(3n) {
  background: var(--signal);
}

.tree-level--one { top: 43%; width: 71%; }
.tree-level--two { top: 72%; width: 91%; }
.tree-level--two i { width: 10px; height: 10px; }

.tree-fade {
  position: absolute;
  inset: 64% 0 0;
  z-index: 3;
  background: linear-gradient(transparent, var(--paper) 78%);
}

.branching-visual p {
  position: absolute;
  right: 0;
  bottom: 1.2rem;
  left: 0;
  z-index: 4;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.62rem;
  text-align: center;
  text-transform: uppercase;
}

.three-questions {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
  background: rgba(255, 255, 255, 0.23);
}

.three-questions article {
  position: relative;
  min-height: 280px;
  padding: 2rem;
  border-right: 1px solid var(--line);
}

.concept-symbol {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border: 1px solid var(--ink);
  border-radius: 50%;
  font-family: var(--display);
  font-size: 1.3rem;
}

.three-questions article:nth-child(2) .concept-symbol { color: var(--paper-bright); background: var(--ink); }
.three-questions article:nth-child(3) .concept-symbol { background: var(--signal); }

.three-questions h3 {
  margin: 2.5rem 0 0.7rem;
  font-family: var(--display);
  font-size: 1.55rem;
  font-weight: 500;
}

.three-questions p {
  color: var(--muted);
  font-size: 0.88rem;
}

.three-questions small {
  position: absolute;
  right: 2rem;
  bottom: 1.5rem;
  left: 2rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.57rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.chapter--blueprint {
  overflow: hidden;
}

.pipeline {
  max-width: var(--content);
  margin: 0 auto;
}

.pipeline-track {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  border: 1px solid var(--line-light);
  border-right: 0;
}

.pipeline-stage {
  position: relative;
  min-height: 172px;
  padding: 1.25rem 1rem;
  color: rgba(255, 255, 255, 0.55);
  border: 0;
  border-right: 1px solid var(--line-light);
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: color 220ms ease, background 220ms ease;
}

.pipeline-stage::after {
  position: absolute;
  right: -8px;
  top: 50%;
  z-index: 3;
  color: rgba(255, 255, 255, 0.33);
  content: "→";
  font-family: var(--mono);
  font-size: 0.7rem;
  transform: translateY(-50%);
}

.pipeline-stage:last-child::after {
  display: none;
}

.pipeline-stage span,
.pipeline-stage strong,
.pipeline-stage small {
  display: block;
}

.pipeline-stage span {
  margin-bottom: 2.5rem;
  font-family: var(--mono);
  font-size: 0.58rem;
}

.pipeline-stage strong {
  color: inherit;
  font-family: var(--display);
  font-size: 1.25rem;
  font-weight: 400;
}

.pipeline-stage small {
  margin-top: 0.25rem;
  font-family: var(--mono);
  font-size: 0.57rem;
}

.pipeline-stage:hover,
.pipeline-stage.is-active {
  color: var(--paper-bright);
  background: rgba(255, 255, 255, 0.055);
}

.pipeline-stage.is-active {
  box-shadow: inset 0 -3px var(--signal);
}

.pipeline-stage.is-active span {
  color: var(--signal);
}

.pipeline-detail {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  min-height: 280px;
  padding: clamp(2rem, 4vw, 4rem);
  color: var(--ink);
  background: var(--signal);
}

.pipeline-detail > div {
  padding-right: 2rem;
}

.pipeline-detail > div + div {
  padding-left: 2rem;
  border-left: 1px solid rgba(21, 23, 17, 0.22);
}

.pipeline-detail .micro-label {
  color: rgba(21, 23, 17, 0.58);
}

.pipeline-detail strong {
  display: block;
  max-width: 270px;
  font-family: var(--display);
  font-size: clamp(1.25rem, 2vw, 1.8rem);
  font-weight: 500;
  line-height: 1.2;
}

.pipeline-detail__index {
  display: block;
  margin-bottom: 1.8rem;
  font-family: var(--mono);
  font-size: 0.6rem;
}

.pipeline-detail__summary {
  grid-column: 1 / -1;
  align-self: end;
  max-width: 850px;
  margin: 2.5rem 0 0;
  padding-top: 1.2rem;
  border-top: 1px solid rgba(21, 23, 17, 0.22);
  font-family: var(--display);
  font-size: clamp(1.25rem, 2.1vw, 1.85rem);
  line-height: 1.3;
}

.policy-system {
  display: grid;
  grid-template-columns: 0.8fr 0.52fr 1.35fr;
  align-items: center;
  gap: 3vw;
  max-width: var(--content);
  min-height: 570px;
  margin: 0 auto;
  padding: clamp(2.5rem, 5vw, 5rem);
  border: 1px solid var(--line);
  background:
    linear-gradient(90deg, rgba(21, 23, 17, 0.027) 1px, transparent 1px),
    linear-gradient(rgba(21, 23, 17, 0.027) 1px, transparent 1px),
    var(--paper-bright);
  background-size: 22px 22px;
}

.feature-stack {
  position: relative;
  min-height: 280px;
}

.stack-card {
  position: absolute;
  display: grid;
  width: 210px;
  height: 210px;
  padding: 1rem;
  border: 1px solid var(--ink);
  background: var(--paper);
  font-family: var(--mono);
  font-size: 0.6rem;
  text-transform: uppercase;
}

.stack-card--back { top: 0; left: 34px; opacity: 0.4; }
.stack-card--mid { top: 24px; left: 17px; opacity: 0.65; }
.stack-card--front { top: 48px; left: 0; align-content: end; background: #cba15d; }

.stack-card strong {
  margin-top: 0.8rem;
  font-family: var(--display);
  font-size: 1.35rem;
  font-weight: 500;
  text-transform: none;
}

.stack-card small {
  text-transform: none;
}

.mini-board {
  position: absolute;
  inset: 1rem 1rem 4.8rem;
  background:
    linear-gradient(90deg, transparent 49%, rgba(21,23,17,.35) 50%, transparent 51%),
    linear-gradient(transparent 49%, rgba(21,23,17,.35) 50%, transparent 51%);
  background-size: 25% 25%;
}

.mini-board span {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--ink);
}

.mini-board span:nth-child(1) { top: 24%; left: 49%; }
.mini-board span:nth-child(2) { top: 49%; left: 24%; background: white; }
.mini-board span:nth-child(3) { top: 49%; left: 49%; }
.mini-board span:nth-child(4) { top: 74%; left: 49%; background: white; }
.mini-board span:nth-child(5) { top: 49%; left: 74%; }

.network-spine {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.55rem;
  text-align: center;
  text-transform: uppercase;
}

.network-spine i {
  display: block;
  width: 78%;
  height: 3px;
  background: var(--ink);
  opacity: 0.22;
}

.network-spine i:nth-of-type(3n) { width: 100%; opacity: 0.62; background: var(--vermillion); }

.network-spine::after {
  margin-top: 0.6rem;
  color: var(--vermillion);
  content: "→";
  font-size: 1rem;
}

.policy-map-wrap {
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--paper);
}

.policy-map-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.8rem;
  font-family: var(--mono);
  font-size: 0.56rem;
  letter-spacing: 0.05em;
}

.policy-map-header strong {
  color: var(--vermillion);
  font-weight: 500;
}

.policy-map {
  display: grid;
  grid-template-columns: repeat(19, 1fr);
  aspect-ratio: 1;
  border: 1px solid rgba(21, 23, 17, 0.25);
  background-color: #cba15d;
  background-image:
    linear-gradient(to right, transparent 48%, rgba(21, 23, 17, 0.3) 50%, transparent 52%),
    linear-gradient(to bottom, transparent 48%, rgba(21, 23, 17, 0.3) 50%, transparent 52%);
  background-size: calc(100% / 18) calc(100% / 18);
}

.policy-cell {
  position: relative;
  z-index: 2;
  border: 0;
  background: transparent;
}

.policy-cell.has-stone::after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 86%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--ink);
  box-shadow: 1px 2px 3px rgba(0, 0, 0, 0.32);
  content: "";
  transform: translate(-50%, -50%);
}

.policy-cell.has-stone.is-white::after {
  background: var(--paper-bright);
  border: 1px solid rgba(21,23,17,.2);
}

.policy-cell.has-signal {
  cursor: help;
}

.policy-cell.has-signal::before {
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 4;
  width: var(--heat-size, 140%);
  aspect-ratio: 1;
  border-radius: 50%;
  background: color-mix(in srgb, var(--signal) var(--heat, 65%), transparent);
  box-shadow: 0 0 14px color-mix(in srgb, var(--signal) 55%, transparent);
  content: "";
  transform: translate(-50%, -50%);
  transition: transform 180ms ease;
}

.policy-cell.has-signal:hover::before,
.policy-cell.has-signal:focus-visible::before {
  transform: translate(-50%, -50%) scale(1.22);
}

.equation-story {
  display: grid;
  grid-template-columns: 1fr 1fr;
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
}

.equation-card {
  padding: clamp(2rem, 4vw, 4rem);
  border-right: 1px solid var(--line);
  background: rgba(255,255,255,.25);
}

.equation-card p:last-child {
  max-width: 460px;
  margin: 1rem 0 0;
  color: var(--muted);
}

.equation {
  overflow-wrap: anywhere;
  font-family: var(--display);
  font-size: clamp(1.7rem, 3.2vw, 3.5rem);
  letter-spacing: -0.035em;
  line-height: 1.16;
}

.equation--dark {
  color: var(--paper-bright);
}

.equation--compact {
  font-size: clamp(1.15rem, 2vw, 1.65rem);
}

.fact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
}

.fact-grid article {
  display: grid;
  align-content: space-between;
  min-height: 175px;
  padding: 1.6rem;
  border-right: 1px solid var(--line);
}

.fact-grid strong {
  font-family: var(--display);
  font-size: clamp(2.2rem, 3.8vw, 4rem);
  font-weight: 400;
  letter-spacing: -0.04em;
}

.fact-grid span {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.61rem;
  text-transform: uppercase;
}

.contrast-note {
  display: grid;
  grid-template-columns: 0.7fr 1.3fr;
  gap: 4rem;
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2rem, 4vw, 4rem);
  color: var(--paper-bright);
  background: var(--ink);
}

.contrast-note h3 {
  max-width: 380px;
  margin: 1rem 0 0;
  font-size: clamp(2rem, 3.3vw, 3.4rem);
}

.policy-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--line-light);
  border-right: 0;
}

.policy-compare article {
  padding: 1.8rem;
  border-right: 1px solid var(--line-light);
}

.policy-compare article > span {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  color: var(--signal);
  border: 1px solid rgba(223,255,69,.38);
  border-radius: 50%;
  font-family: var(--display);
}

.policy-compare h4 {
  margin: 2rem 0 0.3rem;
  font-family: var(--display);
  font-size: 1.4rem;
  font-weight: 400;
}

.policy-compare p,
.policy-compare small {
  color: rgba(255,255,255,.5);
  font-size: 0.72rem;
}

.policy-compare small {
  display: block;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line-light);
}

.objective-shift {
  display: grid;
  grid-template-columns: 1fr 64px 1fr;
  align-items: stretch;
  max-width: var(--content);
  margin: 0 auto 2rem;
}

.objective-card {
  min-height: 230px;
  padding: clamp(2rem, 4vw, 4rem);
  border: 1px solid var(--line-light);
}

.objective-card span {
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: 0.1em;
}

.objective-card p {
  margin: 2.2rem 0 0.65rem;
  font-family: var(--display);
  font-size: clamp(1.8rem, 3vw, 3rem);
  line-height: 1.1;
}

.objective-card code {
  color: rgba(255,255,255,.55);
}

.objective-card--new {
  color: var(--ink);
  border-color: var(--signal);
  background: var(--signal);
}

.objective-card--new code {
  color: var(--ink);
  border-color: rgba(21,23,17,.2);
  background: rgba(21,23,17,.05);
}

.objective-arrow {
  display: grid;
  place-items: center;
  color: var(--signal);
  font-family: var(--mono);
}

.rl-lab {
  display: grid;
  grid-template-columns: 1fr 0.8fr;
  max-width: var(--content);
  margin: 0 auto;
  border: 1px solid var(--line-light);
}

.rl-explanation {
  padding: clamp(2.2rem, 4vw, 4rem);
  border-right: 1px solid var(--line-light);
}

.rl-explanation > p:not(.micro-label) {
  max-width: 650px;
  margin-top: 1.5rem;
  color: rgba(255,255,255,.58);
}

.outcome-toggle {
  display: flex;
  gap: 0.5rem;
  margin-top: 2rem;
}

.outcome-toggle button {
  padding: 0.75rem 0.9rem;
  color: rgba(255,255,255,.6);
  border: 1px solid var(--line-light);
  background: transparent;
  font-family: var(--mono);
  font-size: 0.61rem;
  cursor: pointer;
  transition: all 180ms ease;
}

.outcome-toggle button.is-active {
  color: var(--ink);
  border-color: var(--signal);
  background: var(--signal);
}

.gradient-demo {
  display: grid;
  grid-template-rows: 1fr auto 1fr;
  align-items: center;
  padding: clamp(2rem, 4vw, 4rem);
  background: rgba(255,255,255,.035);
}

.sampled-move,
.gradient-result {
  display: grid;
  padding: 1.5rem;
  border: 1px solid var(--line-light);
}

.sampled-move span,
.gradient-result span,
.sampled-move small,
.gradient-result small {
  color: rgba(255,255,255,.5);
  font-family: var(--mono);
  font-size: 0.6rem;
  text-transform: uppercase;
}

.sampled-move strong,
.gradient-result strong {
  margin: 0.3rem 0;
  color: var(--paper-bright);
  font-family: var(--display);
  font-size: 2.3rem;
  font-weight: 400;
}

.gradient-direction {
  display: grid;
  height: 86px;
  place-items: center;
  color: var(--signal);
  font-size: 2.1rem;
}

.gradient-demo[data-state="loss"] .gradient-direction {
  color: var(--vermillion);
}

.gradient-demo[data-state="loss"] .gradient-result {
  border-color: rgba(231,90,53,.55);
}

.selfplay-loop {
  display: grid;
  grid-template-columns: minmax(320px, .8fr) 1.2fr;
  gap: 5vw;
  align-items: center;
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2.5rem, 5vw, 5rem);
  border: 1px solid var(--line-light);
}

.loop-orbit {
  position: relative;
  aspect-ratio: 1;
  max-width: 360px;
  margin: auto;
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 50%;
}

.loop-orbit::before,
.loop-orbit::after {
  position: absolute;
  inset: 16%;
  border: 1px dashed rgba(255,255,255,.11);
  border-radius: 50%;
  content: "";
}

.loop-orbit::after {
  inset: 34%;
}

.orbit-node {
  position: absolute;
  z-index: 3;
  display: grid;
  width: 92px;
  height: 92px;
  place-items: center;
  border-radius: 50%;
  font-family: var(--mono);
  font-size: 0.65rem;
  line-height: 1.3;
  text-align: center;
}

.orbit-node--current {
  top: 8%;
  left: 8%;
  color: var(--ink);
  background: var(--signal);
}

.orbit-node--past {
  right: 8%;
  bottom: 8%;
  color: var(--paper-bright);
  border: 1px solid rgba(255,255,255,.34);
  background: var(--ink-soft);
}

.orbit-path {
  position: absolute;
  inset: -1px;
  border: 2px solid transparent;
  border-top-color: var(--signal);
  border-radius: 50%;
  animation: orbit 7s linear infinite;
}

@keyframes orbit { to { transform: rotate(360deg); } }

.selfplay-loop h3 {
  margin: 1rem 0;
  font-size: clamp(2rem, 3.6vw, 3.8rem);
}

.selfplay-loop > div:last-child > p:not(.micro-label) {
  color: rgba(255,255,255,.56);
}

.check-list {
  display: grid;
  gap: 0.7rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.check-list li {
  padding: 0.7rem 0 0.7rem 1.8rem;
  border-bottom: 1px solid rgba(255,255,255,.08);
  font-size: 0.82rem;
}

.check-list li::before {
  float: left;
  margin-left: -1.8rem;
  color: var(--signal);
  content: "↳";
  font-family: var(--mono);
}

.value-machine {
  display: grid;
  grid-template-columns: .8fr .7fr .75fr;
  gap: 4vw;
  align-items: center;
  max-width: var(--content);
  min-height: 440px;
  margin: 0 auto;
  padding: clamp(2.5rem, 5vw, 5rem);
  border: 1px solid var(--line);
  background: var(--paper-bright);
}

.value-input {
  display: grid;
  justify-items: center;
  gap: 0.7rem;
}

.value-board {
  position: relative;
  width: min(100%, 270px);
  aspect-ratio: 1;
  background-color: #c99f5b;
  background-image:
    linear-gradient(to right, transparent 48%, rgba(35, 24, 8, 0.42) 50%, transparent 52%),
    linear-gradient(to bottom, transparent 48%, rgba(35, 24, 8, 0.42) 50%, transparent 52%);
  background-size: calc(100% / 12) calc(100% / 12);
  box-shadow: 0 18px 32px rgba(21,23,17,.18);
}

.value-board .stone { width: 7.2%; }
.value-board .s1 { top: 25%; left: 33.2%; }
.value-board .s2 { top: 41.7%; left: 50%; }
.value-board .s3 { top: 50%; left: 41.7%; }
.value-board .s4 { top: 58.3%; left: 58.3%; }
.value-board .s5 { top: 66.7%; left: 41.7%; }
.value-board .s6 { top: 33.2%; left: 66.7%; }

.value-input small,
.value-slider-wrap label,
.mixer-control label {
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: .04em;
  text-transform: uppercase;
}

.value-network {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  place-items: center;
}

.value-network span {
  display: block;
  width: 55px;
  height: 55px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--paper);
  box-shadow: 16px 0 0 -15px rgba(21,23,17,.4);
}

.value-network span:nth-child(2n) { background: var(--ink); }
.value-network span:nth-child(3) { background: var(--signal); }

.value-output {
  display: grid;
  min-height: 230px;
  padding: 2rem;
  align-content: center;
  border: 1px solid var(--ink);
  text-align: center;
}

.value-output > span {
  font-family: var(--mono);
  font-size: .7rem;
}

.value-output strong {
  margin: 1rem 0;
  color: var(--vermillion);
  font-family: var(--display);
  font-size: clamp(3.5rem, 6vw, 6rem);
  font-weight: 400;
  letter-spacing: -.05em;
  line-height: .8;
}

.value-output small {
  color: var(--muted);
  font-family: var(--mono);
  font-size: .63rem;
}

.value-slider-wrap {
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: 2rem clamp(2rem, 4vw, 4rem);
  color: var(--paper-bright);
  background: var(--ink);
}

.value-slider-wrap label {
  display: grid;
  grid-template-columns: 1fr auto auto auto;
  gap: 2rem;
  align-items: center;
}

.value-slider-wrap label span {
  color: rgba(255,255,255,.44);
}

.value-slider-wrap input[type="range"],
.mixer-control input[type="range"],
.candidate-row input[type="range"] {
  background: rgba(255,255,255,.24);
}

.value-slider-wrap input[type="range"]::-webkit-slider-thumb,
.mixer-control input[type="range"]::-webkit-slider-thumb,
.candidate-row input[type="range"]::-webkit-slider-thumb {
  border-color: var(--ink);
  background: var(--signal);
  box-shadow: 0 0 0 1px var(--signal);
}

.value-slider-wrap p {
  margin: .4rem 0 0;
  color: rgba(255,255,255,.48);
  font-size: .75rem;
}

.value-math {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
}

.value-math article {
  min-width: 0;
  padding: clamp(1.8rem, 3vw, 3rem);
  border-right: 1px solid var(--line);
}

.value-math .equation {
  min-height: 100px;
  font-size: clamp(1.35rem, 2.2vw, 2.15rem);
}

.value-math article > p:last-child {
  color: var(--muted);
  font-size: .82rem;
}

.correlation-story {
  display: grid;
  grid-template-columns: .92fr 1.08fr;
  gap: 5vw;
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2.5rem, 5vw, 5rem);
  border: 1px solid var(--line);
  background: var(--paper-bright);
}

.correlation-story h3 {
  margin: 1rem 0;
  font-size: clamp(2rem, 3.4vw, 3.5rem);
}

.correlation-story > div:first-child > p:last-child {
  color: var(--muted);
}

.correlation-compare {
  display: grid;
  gap: 1.6rem;
}

.correlation-compare article {
  padding: 1.3rem;
  border: 1px solid var(--line);
}

.correlation-compare article > span {
  display: block;
  margin-bottom: 1rem;
  font-family: var(--mono);
  font-size: .62rem;
  text-transform: uppercase;
}

.correlation-compare article div {
  display: grid;
  grid-template-columns: 1fr 70px;
  gap: .7rem;
  align-items: center;
  margin: .55rem 0;
}

.correlation-compare article i {
  display: block;
  width: var(--score);
  height: 7px;
  background: var(--vermillion);
}

.correlation-compare article:nth-child(2) i { background: var(--signal-dark); }

.correlation-compare article b {
  font-family: var(--mono);
  font-size: .57rem;
  font-weight: 400;
}

.mcts-stage {
  max-width: var(--content);
  margin: 0 auto;
  border: 1px solid var(--line-light);
}

.phase-tabs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-bottom: 1px solid var(--line-light);
}

.phase-tabs button {
  display: flex;
  align-items: center;
  gap: .8rem;
  padding: 1rem 1.2rem;
  color: rgba(255,255,255,.48);
  border: 0;
  border-right: 1px solid var(--line-light);
  background: transparent;
  font-family: var(--mono);
  font-size: .65rem;
  cursor: pointer;
}

.phase-tabs button:last-child { border-right: 0; }
.phase-tabs button span { color: rgba(255,255,255,.25); }
.phase-tabs button.is-active { color: var(--ink); background: var(--signal); }
.phase-tabs button.is-active span { color: var(--ink); }

.mcts-stage__content {
  display: grid;
  grid-template-columns: 1.35fr .65fr;
  min-height: 590px;
}

.mcts-tree {
  position: relative;
  min-height: 590px;
  overflow: hidden;
  border-right: 1px solid var(--line-light);
  background:
    linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px),
    linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px);
  background-size: 24px 24px;
}

.mcts-tree svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.mcts-tree .edge {
  fill: none;
  stroke: rgba(255,255,255,.22);
  stroke-width: 1.3;
  transition: stroke 300ms ease, stroke-width 300ms ease;
}

.mcts-tree .active-path {
  stroke: var(--signal);
  stroke-width: 2;
  stroke-dasharray: 8 5;
  animation: pathFlow 1.4s linear infinite;
}

@keyframes pathFlow { to { stroke-dashoffset: -26; } }

.tree-node {
  position: absolute;
  z-index: 3;
  display: grid;
  min-width: 78px;
  min-height: 78px;
  padding: .55rem;
  place-items: center;
  color: var(--paper-bright);
  border: 1px solid rgba(255,255,255,.28);
  border-radius: 50%;
  background: var(--ink);
  cursor: default;
  transform: translate(-50%, -50%);
  transition: all 300ms var(--ease);
}

.tree-node span {
  font-family: var(--display);
  font-size: 1.2rem;
  line-height: 1;
}

.tree-node small {
  color: rgba(255,255,255,.42);
  font-family: var(--mono);
  font-size: .45rem;
}

.tree-node.is-path {
  color: var(--ink);
  border-color: var(--signal);
  background: var(--signal);
  box-shadow: 0 0 34px rgba(223,255,69,.18);
}

.tree-node.is-path small { color: rgba(21,23,17,.6); }
.tree-node.is-leaf { border-style: dashed; }

.tree-node--root { top: 12%; left: 50%; }
.tree-node--a { top: 32%; left: 25.7%; }
.tree-node--b { top: 32%; left: 50%; }
.tree-node--c { top: 32%; left: 74.3%; }
.tree-node--ba { top: 58%; left: 35.7%; }
.tree-node--bb { top: 58%; left: 64.3%; }
.tree-node--leaf { top: 82%; left: 35.7%; }

.tree-packet {
  position: absolute;
  z-index: 5;
  top: 76%;
  left: 35.7%;
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  color: var(--ink);
  border-radius: 50%;
  background: var(--vermillion);
  font-family: var(--mono);
  font-size: .6rem;
  opacity: 0;
  transform: translate(-50%,-50%);
}

.mcts-tree[data-phase="evaluation"] .tree-packet {
  opacity: 1;
  animation: packetPulse 1.3s ease-in-out infinite;
}

.mcts-tree[data-phase="backup"] .tree-packet {
  opacity: 1;
  animation: packetBackup 2.5s var(--ease) infinite;
}

@keyframes packetPulse { 50% { box-shadow: 0 0 0 16px rgba(231,90,53,0); transform: translate(-50%,-50%) scale(1.15); } }
@keyframes packetBackup {
  0% { top: 82%; left: 35.7%; }
  45% { top: 58%; left: 35.7%; }
  100% { top: 12%; left: 50%; }
}

.phase-explanation {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: clamp(2rem, 4vw, 4rem);
  background: rgba(255,255,255,.025);
}

.phase-number {
  color: var(--signal);
  font-family: var(--mono);
  font-size: .62rem;
}

.phase-explanation h3 {
  margin: 1.3rem 0 1rem;
  font-family: var(--display);
  font-size: clamp(2rem, 3.2vw, 3.4rem);
  font-weight: 400;
  letter-spacing: -.035em;
  line-height: 1.04;
}

.phase-explanation p {
  color: rgba(255,255,255,.52);
}

.phase-explanation .equation {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line-light);
}

.puct-lab {
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2rem, 4vw, 4rem);
  border: 1px solid var(--line-light);
}

.puct-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 3rem;
}

.puct-heading h3 {
  margin: .8rem 0 0;
  font-size: clamp(2.2rem, 3.5vw, 3.8rem);
}

.puct-heading .equation {
  max-width: 430px;
  padding: 1rem;
  border: 1px solid var(--line-light);
}

.puct-instructions {
  color: rgba(255,255,255,.48);
  font-size: .8rem;
}

.candidate-table {
  margin-top: 2rem;
  border: 1px solid var(--line-light);
}

.candidate-row {
  display: grid;
  grid-template-columns: 70px 1fr 1fr 1fr 90px;
  gap: 1.2rem;
  align-items: center;
  min-height: 92px;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--line-light);
  transition: background 200ms ease, box-shadow 200ms ease;
}

.candidate-row:last-child { border-bottom: 0; }

.candidate-row--head {
  min-height: 44px;
  color: rgba(255,255,255,.35);
  font-family: var(--mono);
  font-size: .55rem;
}

.candidate-row.is-selected {
  color: var(--ink);
  background: var(--signal);
  box-shadow: 0 12px 35px rgba(0,0,0,.2);
}

.candidate-row > strong {
  font-family: var(--display);
  font-size: 2.3rem;
  font-weight: 400;
}

.candidate-row label {
  display: grid;
  grid-template-columns: 1fr 42px;
  gap: .5rem;
  align-items: center;
}

.candidate-row input[type="range"] { margin: 0; }
.candidate-row label output,
.candidate-row > b {
  font-family: var(--mono);
  font-size: .62rem;
  font-weight: 400;
  text-align: right;
}

.candidate-row.is-selected input[type="range"] { background: rgba(21,23,17,.25); }
.candidate-row.is-selected input[type="range"]::-webkit-slider-thumb { border-color: var(--signal); background: var(--ink); box-shadow: 0 0 0 1px var(--ink); }
.candidate-row.is-selected [data-score] { font-size: 1.05rem; font-weight: 500; }

.selection-result {
  display: flex;
  align-items: baseline;
  gap: .55rem;
  margin-top: 1rem;
  padding: 1rem;
  border-left: 3px solid var(--signal);
  background: rgba(255,255,255,.035);
  font-family: var(--mono);
  font-size: .65rem;
}

.selection-result strong { color: var(--signal); }
.selection-result span { color: rgba(255,255,255,.43); }

.leaf-mixer {
  display: grid;
  grid-template-columns: .9fr 1.1fr;
  gap: 5vw;
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2.5rem, 5vw, 5rem);
  border: 1px solid var(--line-light);
}

.leaf-mixer h3 {
  margin: 1rem 0;
  font-size: clamp(2rem, 3.5vw, 3.7rem);
}

.leaf-mixer > div:first-child > p:last-child {
  color: rgba(255,255,255,.5);
}

.mixer-control {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.witness {
  display: grid;
  min-height: 150px;
  padding: 1.2rem;
  align-content: space-between;
  border: 1px solid var(--line-light);
}

.witness span {
  color: rgba(255,255,255,.42);
  font-family: var(--mono);
  font-size: .55rem;
}

.witness strong {
  font-family: var(--display);
  font-size: 2.6rem;
  font-weight: 400;
}

.witness--value strong { color: var(--signal); }
.witness--rollout strong { color: var(--vermillion); }

.mixer-control label,
.mixer-control input,
.mixed-value {
  grid-column: 1 / -1;
}

.mixer-control label {
  display: flex;
  justify-content: space-between;
  margin-top: 1rem;
}

.mixed-value {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem;
  border: 1px solid var(--line-light);
  font-family: var(--mono);
  font-size: .64rem;
}

.mixed-value strong {
  color: var(--signal);
  font-family: var(--display);
  font-size: 2rem;
  font-weight: 400;
}

.mcts-details {
  max-width: var(--content);
  margin: 2rem auto 0;
  border-top: 1px solid var(--line-light);
}

.mcts-details details {
  border-bottom: 1px solid var(--line-light);
}

.mcts-details summary {
  display: flex;
  gap: 1.2rem;
  align-items: center;
  padding: 1.4rem .4rem;
  cursor: pointer;
  font-family: var(--display);
  font-size: 1.35rem;
  list-style: none;
}

.mcts-details summary::-webkit-details-marker { display: none; }
.mcts-details summary span { color: var(--signal); font-family: var(--mono); font-size: .62rem; }
.mcts-details summary::after { margin-left: auto; color: var(--signal); content: "+"; font-family: var(--mono); }
.mcts-details details[open] summary::after { content: "−"; }

.mcts-details details > div {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  padding: .5rem 3.2rem 2.5rem;
}

.mcts-details details p { color: rgba(255,255,255,.52); }

.system-lanes {
  max-width: var(--content);
  margin: 0 auto;
  padding: 2rem;
  border: 1px solid var(--line);
  background: var(--paper-bright);
}

.lane {
  display: grid;
  grid-template-columns: 170px 1fr;
  align-items: center;
}

.lane-title {
  display: grid;
  padding-right: 1.5rem;
}

.lane-title span {
  color: var(--vermillion);
  font-family: var(--display);
  font-size: 2.2rem;
}

.lane-title strong {
  color: var(--muted);
  font-family: var(--mono);
  font-size: .55rem;
  font-weight: 400;
  text-transform: uppercase;
}

.lane-track {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4,1fr);
  min-height: 86px;
  border: 1px solid var(--line);
}

.lane-track > span {
  display: grid;
  place-items: center;
  border-right: 1px solid var(--line);
  font-family: var(--mono);
  font-size: .58rem;
  text-transform: uppercase;
}

.lane-track > span:last-of-type { border-right: 0; }

.lane-packet {
  position: absolute;
  top: 50%;
  left: 2%;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--vermillion);
  box-shadow: 0 0 0 6px rgba(231,90,53,.12);
  transform: translateY(-50%);
  animation: laneTravel 4s ease-in-out infinite;
}

.lane-packet--two { background: var(--signal-dark); animation-delay: -2s; }

@keyframes laneTravel {
  0% { left: 2%; opacity: 0; }
  10% { opacity: 1; }
  90% { opacity: 1; }
  100% { left: 96%; opacity: 0; }
}

.queue-bridge {
  display: flex;
  justify-content: space-around;
  padding: 1.2rem 170px 1.2rem 0;
  color: var(--muted);
  font-family: var(--mono);
  font-size: .55rem;
  text-transform: uppercase;
}

.machine-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
}

.machine-compare article {
  padding: clamp(2rem, 4vw, 4rem);
  border-right: 1px solid var(--line);
}

.machine-compare h3 {
  margin: .8rem 0 2.2rem;
  font-size: clamp(2rem, 3vw, 3.2rem);
}

.hardware-stats {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.hardware-stats span {
  display: grid;
  min-width: 0;
  min-height: 110px;
  padding: 1rem;
  align-content: space-between;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--mono);
  font-size: .55rem;
  text-transform: uppercase;
}

.hardware-stats strong {
  color: var(--ink);
  font-family: var(--display);
  font-size: clamp(1.8rem, 2.8vw, 3rem);
  font-weight: 400;
  letter-spacing: -.04em;
  line-height: 1;
}

.engineering-lessons {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  max-width: var(--content);
  margin: 2rem auto 0;
  border: 1px solid var(--line);
  border-right: 0;
}

.engineering-lessons article {
  min-height: 290px;
  padding: 1.7rem;
  border-right: 1px solid var(--line);
}

.engineering-lessons article > span {
  color: var(--vermillion);
  font-family: var(--mono);
  font-size: .58rem;
}

.engineering-lessons h3 {
  margin: 4rem 0 .8rem;
  font-family: var(--display);
  font-size: 1.6rem;
  font-weight: 400;
  line-height: 1.08;
}

.engineering-lessons p {
  color: var(--muted);
  font-size: .76rem;
}

.result-hero {
  display: grid;
  grid-template-columns: 1.2fr .8fr;
  max-width: var(--content);
  margin: 0 auto;
  border: 1px solid var(--line-light);
}

.result-number,
.fan-hui-score {
  padding: clamp(2.5rem, 5vw, 5rem);
}

.result-number {
  border-right: 1px solid var(--line-light);
}

.result-number span,
.fan-hui-score > span {
  color: rgba(255,255,255,.42);
  font-family: var(--mono);
  font-size: .6rem;
  letter-spacing: .08em;
}

.result-number > strong {
  display: block;
  color: var(--signal);
  font-family: var(--display);
  font-size: clamp(6rem, 12vw, 12rem);
  font-weight: 300;
  letter-spacing: -.07em;
  line-height: .82;
}

.result-number > strong sup {
  font-size: .25em;
  vertical-align: super;
}

.result-number small {
  color: rgba(255,255,255,.48);
  font-family: var(--mono);
  font-size: .65rem;
}

.fan-hui-score > div {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  margin-top: 1.4rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line-light);
}

.fan-hui-score div strong {
  font-family: var(--display);
  font-size: clamp(1.6rem, 2.5vw, 2.5rem);
  font-weight: 400;
}

.fan-hui-score div b {
  color: var(--signal);
  font-family: var(--display);
  font-size: 3.4rem;
  font-weight: 400;
}

.fan-hui-score small {
  display: block;
  margin-top: 1.5rem;
  color: rgba(255,255,255,.46);
  font-size: .75rem;
}

.mental-model {
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2rem, 4vw, 4rem);
  border: 1px solid var(--line-light);
}

.mental-model__grid {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  margin-top: 2rem;
  border: 1px solid var(--line-light);
  border-right: 0;
}

.mental-model__grid article {
  min-height: 230px;
  padding: 1.5rem;
  border-right: 1px solid var(--line-light);
}

.mental-model__grid article > span {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  color: var(--signal);
  border: 1px solid rgba(223,255,69,.36);
  border-radius: 50%;
  font-family: var(--display);
}

.mental-model__grid h3 {
  margin: 3.2rem 0 .5rem;
  font-family: var(--display);
  font-size: 1.5rem;
  font-weight: 400;
}

.mental-model__grid p {
  color: rgba(255,255,255,.46);
  font-size: .75rem;
}

.mental-model blockquote {
  max-width: 980px;
  margin: clamp(3rem, 6vw, 6rem) auto 1rem;
  font-family: var(--display);
  font-size: clamp(2.4rem, 5.2vw, 5.4rem);
  font-weight: 300;
  letter-spacing: -.045em;
  line-height: 1.04;
  text-align: center;
}

.mental-model blockquote::before {
  display: block;
  margin-bottom: 1.5rem;
  color: var(--signal);
  content: "● ○";
  font-family: var(--sans);
  font-size: 1.2rem;
  letter-spacing: .2em;
}

.understanding-check {
  display: grid;
  grid-template-columns: .75fr 1.25fr;
  gap: 5vw;
  max-width: var(--content);
  margin: 2rem auto 0;
  padding: clamp(2.5rem, 5vw, 5rem);
  color: var(--ink);
  background: var(--signal);
}

.understanding-check h3 {
  margin: 1rem 0 0;
  font-size: clamp(2rem, 3.4vw, 3.7rem);
}

.understanding-check .micro-label { color: rgba(21,23,17,.55); }

.understanding-check ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.understanding-check li {
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 1rem;
  align-items: baseline;
  padding: .7rem 0;
  border-bottom: 1px solid rgba(21,23,17,.22);
}

.understanding-check li span {
  font-family: var(--mono);
  font-size: .58rem;
}

.understanding-check li p { margin: 0; font-family: var(--display); font-size: 1.25rem; }

.glossary {
  display: grid;
  grid-template-columns: .65fr 1.35fr;
  gap: 7vw;
  padding: clamp(7rem, 11vw, 11rem) max(8vw, 90px) clamp(7rem, 11vw, 11rem) max(11vw, 130px);
  background: var(--paper-bright);
}

.glossary-heading {
  position: sticky;
  top: 110px;
  align-self: start;
}

.glossary-heading .chapter-kicker { color: var(--muted); }
.glossary-heading h2 { margin-top: 2rem; font-size: clamp(3.4rem, 5vw, 5.8rem); }

.glossary-grid {
  border-top: 1px solid var(--line);
}

.glossary-grid article {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 2rem;
  padding: 1.4rem 0;
  border-bottom: 1px solid var(--line);
}

.glossary-grid article > code {
  align-self: start;
  justify-self: start;
  color: var(--vermillion);
  border: 0;
  background: transparent;
  font-size: .9rem;
}

.glossary-grid strong {
  font-family: var(--display);
  font-size: 1.25rem;
  font-weight: 500;
}

.glossary-grid p {
  margin: .3rem 0 0;
  color: var(--muted);
  font-size: .78rem;
}

.site-footer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3rem;
  align-items: end;
  padding: 4rem max(8vw,90px) 2rem max(11vw,130px);
  color: var(--paper-bright);
  background: var(--ink);
}

.brand--footer { color: var(--paper-bright); }

.site-footer > div:first-child > p {
  margin: 1.5rem 0 0;
  color: rgba(255,255,255,.42);
  font-size: .75rem;
}

.footer-links {
  display: grid;
  gap: .5rem;
  justify-items: end;
}

.footer-links a {
  color: rgba(255,255,255,.68);
  font-family: var(--mono);
  font-size: .64rem;
  text-decoration: none;
}

.footer-links a:hover { color: var(--signal); }

.footer-note {
  grid-column: 1 / -1;
  margin: 2rem 0 0;
  padding-top: 1.4rem;
  color: rgba(255,255,255,.25);
  border-top: 1px solid var(--line-light);
  font-family: var(--mono);
  font-size: .53rem;
  letter-spacing: .04em;
  text-transform: uppercase;
}

.reveal.is-primed {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 900ms var(--ease), transform 900ms var(--ease);
}

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

.reveal--late.is-primed {
  transition-delay: 180ms;
}

@media (max-width: 1280px) {
  .hero {
    grid-template-columns: minmax(0,1fr) minmax(380px,.8fr);
    padding-right: 5vw;
    padding-left: 8vw;
  }

  .hero h1 { font-size: clamp(4rem, 7vw, 6.8rem); }
  .hero-board { width: min(40vw,500px); min-width: 380px; }
  .board-caption { width: min(40vw,500px); }
  .chapter,
  .glossary { padding-right: 6vw; padding-left: 8vw; }
  .thesis-band { padding-right: 6vw; padding-left: 8vw; }
  .site-footer { padding-right: 6vw; padding-left: 8vw; }
}

@media (max-width: 1080px) {
  .chapter-rail { display: none; }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: 135px 7vw 6rem;
  }

  .hero::before { display: none; }
  .hero-copy { max-width: 900px; padding-right: 0; }
  .hero h1 { font-size: clamp(4.6rem, 11vw, 8rem); }
  .hero-lede { max-width: 760px; }
  .hero-visual { margin-top: 6rem; }
  .hero-board { width: min(76vw,620px); min-width: 0; }
  .board-caption { width: min(76vw,620px); }
  .hero-footnote { left: 7vw; }

  .chapter,
  .glossary,
  .thesis-band,
  .site-footer { padding-right: 7vw; padding-left: 7vw; }

  .chapter-heading { grid-template-columns: 1fr; gap: 2rem; }
  .chapter-heading > p:last-child { max-width: 760px; }

  .branching-lab { grid-template-columns: 1fr 1fr; }
  .policy-system { grid-template-columns: .8fr .4fr 1fr; padding: 3rem 2rem; }
  .stack-card { width: 170px; height: 170px; }
  .mcts-stage__content { grid-template-columns: 1fr; }
  .mcts-tree { border-right: 0; border-bottom: 1px solid var(--line-light); }
  .phase-explanation { min-height: 330px; }
  .candidate-row { grid-template-columns: 55px 1fr 1fr 1fr 65px; gap: .7rem; }
  .engineering-lessons { grid-template-columns: 1fr 1fr; }
  .engineering-lessons article:nth-child(2) { border-right: 1px solid var(--line); }
  .engineering-lessons article { border-bottom: 1px solid var(--line); }
}

@media (max-width: 800px) {
  html { scroll-padding-top: 70px; }
  body { font-size: 15px; }
  .site-header { height: 68px; padding: 0 5vw; }
  .header-nav { display: none; }
  .menu-button { display: block; }
  .mobile-nav { inset: 68px 0 auto; }
  .brand { min-width: 0; }

  .hero {
    padding: 110px 5vw 5rem;
  }

  .hero h1 { font-size: clamp(3.8rem, 17vw, 6.5rem); }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 1.2rem; }
  .hero-stats { display: grid; grid-template-columns: repeat(3,1fr); width: 100%; gap: .75rem; }
  .hero-stats div { padding-left: .55rem; }
  .hero-stats dd { font-size: .5rem; }
  .hero-visual { margin-top: 5rem; }
  .hero-board { width: 90vw; }
  .board-caption { width: 90vw; margin-left: 0; }
  .hero-footnote { display: none; }

  .thesis-band { grid-template-columns: 1fr; gap: 1rem; padding: 4rem 5vw; }
  .thesis-band > p { margin: 0; }
  .chapter,
  .glossary { padding: 6.5rem 5vw; }
  .chapter-heading { margin-bottom: 4rem; }
  .chapter-heading h2,
  .glossary-heading h2 { font-size: clamp(3.2rem, 14vw, 5.6rem); }

  .branching-lab { grid-template-columns: 1fr; }
  .branching-copy { border-right: 0; border-bottom: 1px solid var(--line); }
  .branching-visual { min-height: 420px; }
  .three-questions { grid-template-columns: 1fr; border-bottom: 0; }
  .three-questions article { min-height: 240px; border-bottom: 1px solid var(--line); }

  .pipeline-track {
    grid-template-columns: 1fr 1fr;
  }
  .pipeline-stage { min-height: 125px; }
  .pipeline-stage span { margin-bottom: 1rem; }
  .pipeline-stage::after { display: none; }
  .pipeline-detail { grid-template-columns: 1fr; gap: 1.5rem; }
  .pipeline-detail > div + div { padding: 1.5rem 0 0; border-top: 1px solid rgba(21,23,17,.2); border-left: 0; }

  .policy-system { grid-template-columns: 1fr; gap: 2rem; }
  .feature-stack { min-height: 250px; width: 220px; margin: auto; }
  .stack-card { width: 180px; height: 180px; }
  .network-spine { flex-direction: row; flex-wrap: wrap; justify-content: center; }
  .network-spine i { width: 3px; height: 36px; }
  .network-spine i:nth-of-type(3n) { width: 3px; height: 48px; }
  .network-spine::after { margin: 0 0 0 .5rem; }
  .policy-map-wrap { width: 100%; max-width: 430px; margin: auto; }
  .equation-story,
  .fact-grid,
  .policy-compare,
  .value-math,
  .machine-compare,
  .mental-model__grid { grid-template-columns: 1fr 1fr; }
  .contrast-note { grid-template-columns: 1fr; gap: 2rem; }

  .objective-shift { grid-template-columns: 1fr; }
  .objective-arrow { height: 56px; transform: rotate(90deg); }
  .rl-lab,
  .selfplay-loop,
  .value-machine,
  .correlation-story,
  .leaf-mixer,
  .result-hero,
  .understanding-check { grid-template-columns: 1fr; }
  .rl-explanation { border-right: 0; border-bottom: 1px solid var(--line-light); }
  .gradient-demo { min-height: 500px; }
  .loop-orbit { width: min(90%, 350px); }

  .value-machine { gap: 3rem; }
  .value-network { grid-template-columns: repeat(6,1fr); }
  .value-network span { width: 34px; height: 34px; }
  .value-output { width: min(100%, 340px); margin: auto; }
  .value-slider-wrap label { grid-template-columns: 1fr; gap: .5rem; }
  .value-slider-wrap label span { display: none; }

  .phase-tabs { grid-template-columns: 1fr 1fr; }
  .phase-tabs button:nth-child(2) { border-right: 0; }
  .phase-tabs button:nth-child(-n+2) { border-bottom: 1px solid var(--line-light); }
  .mcts-stage__content,
  .mcts-tree { min-height: 500px; }
  .puct-heading { align-items: start; flex-direction: column; gap: 1rem; }
  .candidate-row--head { display: none; }
  .candidate-row { grid-template-columns: 48px 1fr; gap: .8rem; padding: 1.2rem; }
  .candidate-row > strong { grid-row: 1 / 5; }
  .candidate-row label { grid-column: 2; }
  .candidate-row > b { grid-column: 2; justify-self: end; }
  .selection-result { align-items: flex-start; flex-direction: column; }
  .mcts-details details > div { grid-template-columns: 1fr; gap: 1rem; padding-left: 2rem; }

  .lane { grid-template-columns: 1fr; gap: .8rem; }
  .lane-title { padding-right: 0; }
  .queue-bridge { padding-right: 0; }
  .hardware-stats { grid-template-columns: repeat(3,1fr); }
  .engineering-lessons { grid-template-columns: 1fr 1fr; }
  .result-number { border-right: 0; border-bottom: 1px solid var(--line-light); }

  .glossary { grid-template-columns: 1fr; }
  .glossary-heading { position: static; }
  .site-footer { grid-template-columns: 1fr; padding: 4rem 5vw 2rem; }
  .footer-links { justify-items: start; }
}

@media (max-width: 520px) {
  .hero h1 { font-size: clamp(3.5rem, 19vw, 5.1rem); }
  .hero-lede { font-size: 1.15rem; }
  .button { width: 100%; min-width: 0; }
  .eyebrow { align-items: flex-start; flex-wrap: wrap; gap: .45rem; }
  .eyebrow::before { margin-top: .45rem; }
  .hero-stats { grid-template-columns: 1fr; }
  .hero-stats div { display: grid; grid-template-columns: 90px 1fr; align-items: center; }
  .hero-stats dd { margin: 0; }
  .board-caption { grid-template-columns: 28px 1fr; }

  .chapter-heading h2,
  .glossary-heading h2 { font-size: clamp(3rem, 16vw, 4.7rem); }
  .pipeline-track { grid-template-columns: 1fr; }
  .pipeline-stage { min-height: 96px; }
  .pipeline-stage span { margin-bottom: .3rem; }
  .equation-story,
  .fact-grid,
  .policy-compare,
  .value-math,
  .machine-compare,
  .mental-model__grid,
  .engineering-lessons { grid-template-columns: 1fr; }
  .equation-card,
  .fact-grid article,
  .policy-compare article,
  .value-math article,
  .machine-compare article,
  .mental-model__grid article,
  .engineering-lessons article { border-bottom: 1px solid var(--line); }
  .policy-system { padding: 2rem 1rem; }
  .policy-map-header { align-items: flex-start; flex-direction: column; gap: .3rem; }
  .outcome-toggle { flex-direction: column; }
  .value-network { grid-template-columns: repeat(3,1fr); }
  .mcts-tree { min-height: 440px; }
  .tree-node { min-width: 58px; min-height: 58px; }
  .tree-node small { display: none; }
  .phase-explanation { min-height: 380px; }
  .mixer-control { grid-template-columns: 1fr; }
  .witness,
  .mixer-control label,
  .mixer-control input,
  .mixed-value { grid-column: 1; }
  .mixed-value { align-items: flex-start; flex-direction: column; gap: .7rem; }
  .lane-track { grid-template-columns: 1fr 1fr; }
  .lane-track > span { min-height: 64px; border-bottom: 1px solid var(--line); }
  .queue-bridge { flex-direction: column; gap: .4rem; }
  .hardware-stats { grid-template-columns: 1fr; }
  .understanding-check li p { font-size: 1.05rem; }
  .glossary-grid article { grid-template-columns: 95px 1fr; gap: 1rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}