:root {
  --paper: #eef1eb;
  --paper-deep: #dfe5dd;
  --ink: #172019;
  --ink-soft: #39443c;
  --muted: #68736b;
  --line: #c6cec6;
  --line-dark: rgba(245, 247, 241, 0.18);
  --red: #b43c2e;
  --red-dark: #8b2a21;
  --jade: #24685c;
  --brass: #b4863c;
  --night: #101713;
  --night-soft: #17211c;
  --white: #f5f7f1;
  --max-width: 1240px;
  --radius: 8px;
  --header-height: 74px;
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--paper);
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
  font-size: 16px;
  line-height: 1.8;
  overflow-x: hidden;
}

body.is-loading {
  overflow: hidden;
}

::selection {
  background: var(--red);
  color: var(--white);
}

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

a {
  color: inherit;
}

button,
input {
  font: inherit;
}

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

button {
  color: inherit;
}

.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;
}

.loader {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 12px;
  padding: 32px;
  background: var(--night);
  color: var(--white);
  opacity: 1;
  visibility: visible;
  transition:
    opacity 500ms var(--ease),
    visibility 500ms var(--ease);
}

body.is-loaded .loader {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.loader__geometry {
  width: 132px;
  height: 132px;
  margin-bottom: 8px;
}

.loader__geometry svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.loader__geometry circle,
.loader__geometry polygon {
  fill: none;
  stroke: var(--white);
  stroke-width: 1;
  vector-effect: non-scaling-stroke;
}

.loader__geometry circle:first-child {
  stroke-opacity: 0.28;
  stroke-dasharray: 3 7;
}

.loader__geometry polygon {
  stroke: var(--red);
  stroke-width: 2;
  transform-origin: center;
  animation: loader-turn 4s linear infinite;
}

.loader__geometry .loader__dot {
  fill: var(--white);
  stroke: none;
}

.loader__eyebrow,
.loader__title,
.loader__percent {
  margin: 0;
}

.loader__eyebrow {
  color: rgba(245, 247, 241, 0.62);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
}

.loader__title {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.5rem;
}

.loader__track {
  width: 180px;
  height: 1px;
  margin-top: 18px;
  overflow: hidden;
  background: rgba(245, 247, 241, 0.15);
}

.loader__track span {
  display: block;
  width: 0%;
  height: 100%;
  background: var(--red);
}

.loader__percent {
  color: rgba(245, 247, 241, 0.52);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}

@keyframes loader-turn {
  to {
    transform: rotate(360deg);
  }
}

.scroll-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 220;
  height: 2px;
  background: rgba(23, 32, 25, 0.08);
  pointer-events: none;
}

.scroll-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--red);
}

.site-header {
  position: fixed;
  inset: 2px 0 auto;
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  padding: 0 28px;
  border-bottom: 1px solid rgba(23, 32, 25, 0.12);
  background: rgba(238, 241, 235, 0.84);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  color: var(--ink);
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 14px;
  text-decoration: none;
}

.brand span {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.1rem;
  font-weight: 600;
}

.brand small {
  color: var(--muted);
  font-size: 0.7rem;
}

.chapter-counter {
  display: flex;
  gap: 6px;
  margin: 0;
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
}

.chapter-counter span:first-child {
  color: var(--red);
  font-weight: 700;
}

.chapter-counter span:last-child {
  color: var(--muted);
}

.chapter-rail {
  position: fixed;
  top: 50%;
  right: 22px;
  z-index: 180;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transform: translateY(-50%);
}

.chapter-rail a {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 9px;
  min-height: 32px;
  color: var(--muted);
  text-decoration: none;
}

.chapter-rail a span {
  font-size: 0.62rem;
  font-variant-numeric: tabular-nums;
  opacity: 0.5;
}

.chapter-rail a em {
  position: relative;
  display: block;
  width: 24px;
  height: 1px;
  overflow: hidden;
  background: currentColor;
  font-size: 0;
}

.chapter-rail a em::after {
  position: absolute;
  inset: 0;
  background: var(--red);
  content: "";
  transform: translateX(-102%);
  transition: transform 260ms var(--ease);
}

.chapter-rail a.is-active {
  color: var(--ink);
}

.chapter-rail.is-on-dark a {
  color: rgba(245, 247, 241, 0.42);
}

.chapter-rail.is-on-dark a.is-active {
  color: var(--white);
}

.chapter-rail.is-on-dark a em {
  background: rgba(245, 247, 241, 0.28);
}

.chapter-rail a.is-active em {
  width: 42px;
}

.chapter-rail a.is-active em::after,
.chapter-rail a:hover em::after,
.chapter-rail a:focus-visible em::after {
  transform: translateX(0);
}

.chapter {
  position: relative;
  isolation: isolate;
  scroll-margin-top: var(--header-height);
}

.section-shell {
  position: relative;
  z-index: 1;
  width: min(calc(100% - 56px), var(--max-width));
  margin: 0 auto;
}

.section-backdrop {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  pointer-events: none;
}

.section-backdrop--problem {
  object-position: right center;
  opacity: 0.82;
}

.section-backdrop--culture {
  object-position: right center;
  opacity: 0.78;
}

.section-backdrop--experiment {
  object-position: right center;
  opacity: 0.72;
}

.section-backdrop--discovery {
  object-position: right center;
  opacity: 0.88;
}

.section-backdrop--legacy {
  object-position: right bottom;
  opacity: 0.8;
}

.section-backdrop--share {
  object-position: center;
  opacity: 0.72;
}

.hero {
  min-height: 100svh;
  overflow: hidden;
  padding: calc(var(--header-height) + 34px) 0 52px;
  background:
    linear-gradient(rgba(245, 247, 241, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 247, 241, 0.06) 1px, transparent 1px),
    var(--night);
  background-size: 72px 72px;
  color: var(--white);
}

.hero::before {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(16, 23, 19, 0.98) 0%, rgba(16, 23, 19, 0.88) 42%, transparent 74%),
    linear-gradient(0deg, rgba(16, 23, 19, 0.6), transparent 45%);
  content: "";
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 2;
  width: min(calc(100% - 56px), var(--max-width));
  margin: 0 auto;
  padding-top: 7vh;
}

.eyebrow,
.section-kicker {
  margin: 0 0 20px;
  color: var(--red);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 8ch;
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 7.4rem;
  font-weight: 500;
  line-height: 0.94;
}

.hero h1 span {
  display: block;
}

.hero__dek {
  max-width: 44ch;
  margin: 32px 0 0;
  color: rgba(245, 247, 241, 0.75);
  font-size: 1.02rem;
  line-height: 1.85;
}

.hero__manifesto {
  max-width: 42ch;
  margin: 20px 0 0;
  color: rgba(245, 247, 241, 0.54);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 0.92rem;
  line-height: 1.85;
}

.hero__cue {
  display: inline-flex;
  align-items: center;
  gap: 18px;
  min-height: 48px;
  margin-top: 38px;
  color: var(--white);
  font-size: 0.82rem;
  text-decoration: none;
}

.hero__keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  max-width: 480px;
  margin: 34px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid rgba(245, 247, 241, 0.14);
  list-style: none;
  color: rgba(245, 247, 241, 0.44);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
}

.hero__keywords li {
  position: relative;
  padding-left: 11px;
}

.hero__keywords li::before {
  position: absolute;
  top: 50%;
  left: 0;
  width: 4px;
  height: 4px;
  background: var(--red);
  content: "";
  transform: translateY(-50%);
}

.hero__cue i {
  position: relative;
  display: block;
  width: 72px;
  height: 1px;
  background: rgba(245, 247, 241, 0.44);
}

.hero__cue i::after {
  position: absolute;
  top: -3px;
  right: 0;
  width: 7px;
  height: 7px;
  border-right: 1px solid var(--white);
  border-bottom: 1px solid var(--white);
  content: "";
  transform: rotate(-45deg);
}

.hero__cue:hover i,
.hero__cue:focus-visible i {
  background: var(--red);
}

.hero__figure {
  position: absolute;
  z-index: 1;
  right: max(2vw, 24px);
  bottom: clamp(14px, 3vh, 48px);
  width: min(56vw, 720px);
  color: rgba(245, 247, 241, 0.7);
}

.hero__figure--art {
  right: -7vw;
  bottom: -12vh;
  width: min(76vw, 1000px);
  opacity: 0.9;
}

.hero__figure--art img {
  width: 100%;
  height: auto;
}

.hero__figure svg {
  width: 100%;
  height: auto;
}

.hero__grid line,
.hero__grid circle {
  fill: none;
  stroke: currentColor;
  stroke-width: 1;
  opacity: 0.2;
}

.hero__circle {
  fill: none;
  stroke: var(--white);
  stroke-width: 1;
  opacity: 0.52;
}

.hero__circle--dash {
  stroke: rgba(245, 247, 241, 0.42);
  stroke-dasharray: 4 10;
}

.hero__polygon {
  fill: rgba(180, 60, 46, 0.1);
  stroke: var(--red);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

.hero__radius {
  stroke: var(--red);
  stroke-width: 1;
  opacity: 0.65;
}

.hero__center {
  fill: var(--white);
}

.hero__figure-label {
  margin: -2% 0 0 18%;
  color: rgba(245, 247, 241, 0.44);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
}

.hero__side-note {
  position: absolute;
  bottom: 34px;
  left: 28px;
  z-index: 2;
  margin: 0;
  color: rgba(245, 247, 241, 0.36);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  writing-mode: vertical-rl;
}

.chapter--paper {
  padding: 120px 0;
  background: var(--paper);
}

.chapter--lab {
  padding: 112px 0;
  background:
    linear-gradient(rgba(23, 32, 25, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(23, 32, 25, 0.035) 1px, transparent 1px),
    var(--paper-deep);
  background-size: 48px 48px;
}

.chapter--culture {
  padding: 124px 0;
  background:
    linear-gradient(rgba(245, 247, 241, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 247, 241, 0.035) 1px, transparent 1px),
    #17352d;
  background-size: 64px 64px;
  color: var(--white);
}

.chapter--dark {
  padding: 132px 0;
  background: var(--night-soft);
  color: var(--white);
}

.chapter--night {
  min-height: 100svh;
  overflow: hidden;
  padding: 132px 0 100px;
  background: var(--night);
  color: var(--white);
}

.section-heading {
  max-width: 820px;
  margin-bottom: 56px;
}

.section-heading h2 {
  max-width: 15ch;
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 3.8rem;
  font-weight: 500;
  line-height: 1.17;
}

.section-intro {
  max-width: 58ch;
  margin: 26px 0 0;
  color: var(--muted);
  font-size: 1rem;
}

.section-heading--light .section-intro {
  color: rgba(245, 247, 241, 0.62);
}

.section-heading--light .section-intro,
.section-heading--light .section-kicker {
  color: rgba(245, 247, 241, 0.64);
}

.section-heading--light .section-kicker {
  color: var(--red);
}

.section-heading--culture .section-kicker {
  color: var(--brass);
}

.section-heading--culture .section-intro {
  max-width: 68ch;
  color: rgba(245, 247, 241, 0.64);
}

.culture-lead {
  max-width: 72ch;
  margin: -18px 0 46px;
  color: rgba(245, 247, 241, 0.6);
  font-size: 0.92rem;
  line-height: 1.95;
}

.culture-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 1px solid rgba(245, 247, 241, 0.18);
  border-bottom: 1px solid rgba(245, 247, 241, 0.18);
}

.culture-item {
  min-width: 0;
  padding: 30px 22px 34px 0;
}

.culture-item + .culture-item {
  padding-right: 0;
  padding-left: 22px;
  border-left: 1px solid rgba(245, 247, 241, 0.18);
}

.culture-item__visual {
  position: relative;
  aspect-ratio: 420 / 260;
  overflow: hidden;
  border: 1px solid rgba(245, 247, 241, 0.12);
  border-radius: var(--radius);
  background: #101713;
}

.culture-image-trigger {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  padding: 0;
  overflow: hidden;
  border: 0;
  background: transparent;
  cursor: zoom-in;
}

.culture-image-trigger img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  transition: transform 500ms var(--ease);
}

.culture-image-trigger:hover img,
.culture-image-trigger:focus-visible img {
  transform: scale(1.02);
}

.culture-image-trigger:focus-visible {
  outline: 2px solid var(--brass);
  outline-offset: -4px;
}

.culture-item__index {
  position: absolute;
  top: 14px;
  left: 16px;
  z-index: 1;
  color: rgba(245, 247, 241, 0.38);
  font-size: 0.64rem;
  font-variant-numeric: tabular-nums;
}

.culture-svg__grid {
  fill: none;
  stroke: rgba(245, 247, 241, 0.1);
  stroke-width: 1;
}

.culture-svg__line {
  fill: none;
  stroke: rgba(245, 247, 241, 0.48);
  stroke-width: 1;
}

.culture-svg__accent {
  fill: none;
  stroke: var(--red);
  stroke-width: 1.7;
}

.culture-svg__river {
  fill: none;
  stroke: var(--brass);
  stroke-width: 1.4;
}

.culture-svg__point {
  fill: var(--red);
  stroke: none;
}

.culture-item__meta {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  margin-top: 18px;
  padding-top: 12px;
  border-top: 1px solid rgba(245, 247, 241, 0.16);
  color: rgba(245, 247, 241, 0.48);
  font-size: 0.68rem;
}

.culture-item__meta span:last-child {
  color: var(--brass);
}

.culture-item h3 {
  margin: 20px 0 10px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.7rem;
  font-weight: 500;
}

.culture-item p {
  max-width: 35ch;
  margin: 0;
  color: rgba(245, 247, 241, 0.62);
  font-size: 0.82rem;
}

.culture-item .culture-modern {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid rgba(245, 247, 241, 0.14);
  color: rgba(245, 247, 241, 0.48);
  font-size: 0.72rem;
  line-height: 1.75;
}

.culture-modern span {
  display: block;
  margin-bottom: 3px;
  color: var(--brass);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
}

.culture-pullquote {
  max-width: 900px;
  margin: 94px 0 0 auto;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 2.6rem;
  line-height: 1.52;
  text-align: right;
}

.culture-note {
  display: flex;
  align-items: baseline;
  gap: 22px;
  margin-top: 54px;
  color: rgba(245, 247, 241, 0.42);
  font-size: 0.7rem;
}

.culture-note span {
  flex: 0 0 auto;
  color: var(--brass);
}

.culture-note p {
  margin: 0;
}

.problem-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 0.74fr);
  gap: 72px;
  align-items: start;
}

.chapter-bridge {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 42px;
  margin: 0 0 42px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.chapter-bridge p {
  margin: 0;
  color: var(--ink-soft);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.02rem;
  line-height: 1.85;
}

.chapter-bridge p:first-child {
  color: var(--muted);
}

.polygon-compare {
  display: grid;
  gap: 28px;
  margin-bottom: 42px;
  padding: 28px 0 32px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.polygon-compare__intro {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  grid-template-areas:
    "kicker copy"
    "title copy";
  gap: 42px;
  align-items: end;
}

.polygon-compare__intro .section-kicker {
  grid-area: kicker;
  margin: 0;
}

.polygon-compare__intro h3 {
  grid-area: title;
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 2rem;
  font-weight: 500;
}

.polygon-compare__intro > p:last-child {
  grid-area: copy;
  max-width: 48ch;
  margin: 0;
  color: var(--muted);
}

.polygon-compare__grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.compare-figure {
  margin: 0;
  padding: 14px 14px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(245, 247, 241, 0.2);
}

.compare-figure svg {
  width: 100%;
  max-height: 210px;
}

.compare-figure circle {
  fill: none;
  stroke: var(--ink);
  stroke-opacity: 0.34;
  stroke-width: 1;
}

.compare-polygon {
  fill: rgba(180, 60, 46, 0.07);
  stroke: var(--red);
  stroke-width: 1.4;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
}

.compare-figure figcaption {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  margin-top: 6px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.67rem;
  font-variant-numeric: tabular-nums;
}

.compare-figure figcaption strong {
  color: var(--ink);
  font-weight: 500;
}

.polygon-compare__formula {
  display: grid;
  gap: 12px;
  padding: 22px 0 0;
  border-top: 1px solid var(--line);
}

.polygon-compare__formula p {
  max-width: 78ch;
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.85;
}

.formula-line {
  color: var(--red) !important;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.8rem !important;
  font-variant-numeric: tabular-nums;
}

.problem-copy {
  padding-top: 16px;
}

.problem-copy p {
  max-width: 56ch;
  margin: 0 0 24px;
  color: var(--ink-soft);
}

.problem-copy .lead {
  color: var(--ink);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.5rem;
  line-height: 1.7;
}

.fact-list {
  display: grid;
  grid-template-columns: repeat(3, max-content);
  gap: 18px 36px;
  margin: 48px 0 0;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.fact-list div {
  display: grid;
  gap: 4px;
}

.fact-list dt {
  color: var(--muted);
  font-size: 0.72rem;
}

.fact-list dd {
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.02rem;
}

.media-slot {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  min-height: 440px;
  margin: 0;
  padding: 24px;
  overflow: hidden;
  border: 1px solid var(--line);
  background:
    linear-gradient(rgba(23, 32, 25, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(23, 32, 25, 0.06) 1px, transparent 1px),
    rgba(255, 255, 255, 0.22);
  background-size: 32px 32px;
}

.media-slot::before,
.media-slot::after {
  position: absolute;
  width: 18px;
  height: 18px;
  border-color: var(--red);
  border-style: solid;
  content: "";
}

.media-slot::before {
  top: 14px;
  left: 14px;
  border-width: 1px 0 0 1px;
}

.media-slot::after {
  right: 14px;
  bottom: 14px;
  border-width: 0 1px 1px 0;
}

.media-slot--portrait {
  min-height: 500px;
}

.media-slot--wide {
  min-height: 430px;
  margin-top: 72px;
}

.media-slot__tag {
  position: absolute;
  top: 22px;
  left: 22px;
  color: var(--red);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
}

.media-slot__graphic {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 160px;
  height: 160px;
  border: 1px solid rgba(23, 32, 25, 0.28);
  border-radius: 50%;
  transform: translate(-50%, -58%);
}

.media-slot__graphic::before,
.media-slot__graphic::after {
  position: absolute;
  inset: 18%;
  border: 1px solid rgba(180, 60, 46, 0.5);
  content: "";
  transform: rotate(45deg);
}

.media-slot__graphic::after {
  inset: 33%;
  border-color: rgba(23, 32, 25, 0.3);
  border-radius: 50%;
  transform: none;
}

.media-slot__graphic--wide {
  width: 220px;
  height: 140px;
  border-radius: 0;
  transform: translate(-50%, -66%);
}

.media-slot__graphic--wide::before {
  inset: 0;
  border-color: rgba(23, 32, 25, 0.2);
  transform: none;
}

.media-slot__graphic--wide::after {
  inset: 28px;
  border-radius: 0;
  transform: rotate(-9deg);
}

.media-slot figcaption {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 7px;
  max-width: 420px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.media-slot figcaption strong {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.1rem;
  font-weight: 500;
}

.media-slot figcaption span {
  color: var(--muted);
  font-size: 0.78rem;
}

.archive-image {
  margin: 0;
}

.archive-image__trigger {
  position: relative;
  display: block;
  width: 100%;
  padding: 0;
  overflow: hidden;
  border: 0;
  border-radius: var(--radius);
  background: var(--paper-deep);
  cursor: zoom-in;
}

.archive-image__trigger img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 500ms var(--ease);
}

.archive-image__trigger:hover img,
.archive-image__trigger:focus-visible img {
  transform: scale(1.015);
}

.archive-image__trigger:focus-visible {
  outline: 2px solid var(--red);
  outline-offset: 4px;
}

.archive-image--portrait .archive-image__trigger {
  aspect-ratio: 582 / 703;
}

.archive-image--wide {
  margin-top: 72px;
}

.archive-image--wide .archive-image__trigger {
  aspect-ratio: 1111 / 679;
  background: #f4f2ea;
}

.archive-image--wide img {
  object-fit: contain;
}

.archive-image--document {
  max-width: 620px;
  margin: 64px auto 0;
  padding: 18px;
  border: 1px solid rgba(245, 247, 241, 0.16);
  border-radius: var(--radius);
  background: #e7e8e1;
  color: var(--ink);
}

.archive-image--document .archive-image__trigger {
  aspect-ratio: 400 / 243;
}

.archive-image--document img {
  object-fit: contain;
  background: #171b18;
}

.archive-image__zoom {
  position: absolute;
  right: 14px;
  bottom: 14px;
  padding: 6px 10px;
  border-radius: 4px;
  background: rgba(16, 23, 19, 0.78);
  color: var(--white);
  font-size: 0.64rem;
}

.archive-image figcaption {
  display: grid;
  gap: 5px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}

.archive-image figcaption strong {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1rem;
  font-weight: 500;
}

.archive-image figcaption span {
  color: var(--muted);
  font-size: 0.72rem;
}

.archive-image--document figcaption {
  border-color: rgba(23, 32, 25, 0.18);
}

.archive-image--document figcaption span {
  color: var(--ink-soft);
}

.lab-shell {
  display: grid;
  grid-template-columns: minmax(0, 1.16fr) minmax(320px, 0.84fr);
  overflow: hidden;
  border: 1px solid rgba(23, 32, 25, 0.18);
  border-radius: var(--radius);
  background: rgba(245, 247, 241, 0.64);
}

.lab-stage {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 620px;
  padding: 42px;
  overflow: hidden;
  background: var(--night);
  color: var(--white);
}

.lab-stage::before {
  position: absolute;
  inset: 18px;
  border: 1px solid rgba(245, 247, 241, 0.1);
  content: "";
  pointer-events: none;
}

.lab-stage svg {
  width: min(100%, 540px);
  height: auto;
  overflow: visible;
}

.lab-axis {
  stroke: rgba(245, 247, 241, 0.2);
  stroke-width: 1;
  stroke-dasharray: 4 8;
}

.lab-guide {
  fill: none;
  stroke: rgba(245, 247, 241, 0.44);
  stroke-width: 1;
}

.lab-guide--dash {
  stroke: rgba(245, 247, 241, 0.2);
  stroke-dasharray: 3 9;
}

.lab-polygon {
  fill: rgba(180, 60, 46, 0.08);
  stroke: var(--red);
  stroke-width: 1.8;
  stroke-linejoin: round;
  vector-effect: non-scaling-stroke;
  transform-origin: center;
}

.lab-radius {
  stroke: var(--brass);
  stroke-width: 1;
}

.lab-center {
  fill: var(--white);
}

.lab-label {
  fill: var(--brass);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 16px;
}

.vertex-dot {
  fill: var(--red);
}

.lab-stage__caption {
  position: absolute;
  right: 34px;
  bottom: 26px;
  margin: 0;
  color: rgba(245, 247, 241, 0.4);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
}

.lab-controls {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 42px;
}

.lab-readout {
  display: grid;
  gap: 22px;
  margin-bottom: 36px;
}

.lab-readout div {
  display: grid;
  grid-template-columns: 1fr minmax(0, 1.45fr);
  align-items: baseline;
  gap: 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.lab-readout span {
  color: var(--muted);
  font-size: 0.76rem;
}

.lab-readout strong {
  overflow-wrap: anywhere;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.7rem;
  font-weight: 500;
  line-height: 1.25;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.lab-readout div:first-child strong {
  color: var(--red);
}

.precision-meter {
  display: grid;
  gap: 10px;
  margin-bottom: 30px;
}

.precision-meter__head {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  color: var(--muted);
  font-size: 0.72rem;
}

.precision-meter__head strong {
  color: var(--red);
  font-variant-numeric: tabular-nums;
}

.precision-meter__track {
  position: relative;
  height: 12px;
}

.precision-meter__track::before {
  position: absolute;
  top: 5px;
  right: 0;
  left: 0;
  height: 2px;
  background: var(--line);
  content: "";
}

.precision-meter__track span {
  position: absolute;
  top: 5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--red);
  transition: width 420ms var(--ease);
}

.precision-meter__track i {
  position: absolute;
  top: 6px;
  left: 0;
  width: 12px;
  height: 12px;
  border: 3px solid var(--paper-deep);
  border-radius: 50%;
  background: var(--red);
  transform: translate(-50%, -50%);
  transition: left 420ms var(--ease);
}

.precision-meter__labels {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.62rem;
  font-variant-numeric: tabular-nums;
}

.range-wrap {
  display: grid;
  gap: 10px;
}

.range-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
}

.range-head label {
  font-size: 0.82rem;
  font-weight: 600;
}

.range-head > span {
  color: var(--muted);
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
}

.range-head > span strong {
  color: var(--red);
  font-weight: 500;
}

.range {
  width: 100%;
  height: 28px;
  margin: 0;
  background: transparent;
  appearance: none;
  cursor: pointer;
}

.range::-webkit-slider-runnable-track {
  height: 2px;
  background: var(--line);
}

.range::-moz-range-track {
  height: 2px;
  background: var(--line);
}

.range::-webkit-slider-thumb {
  width: 20px;
  height: 20px;
  margin-top: -9px;
  border: 5px solid var(--paper-deep);
  border-radius: 50%;
  background: var(--red);
  box-shadow: 0 0 0 1px var(--red);
  appearance: none;
}

.range::-moz-range-thumb {
  width: 12px;
  height: 12px;
  border: 4px solid var(--paper-deep);
  border-radius: 50%;
  background: var(--red);
  box-shadow: 0 0 0 1px var(--red);
}

.range-marks {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.66rem;
  font-variant-numeric: tabular-nums;
}

.range-marks span:first-child {
  color: var(--red);
}

.field-help,
.lab-note {
  margin: 0;
  color: var(--muted);
  font-size: 0.72rem;
}

.preset-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-top: 28px;
}

.preset-row button {
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: transparent;
  font-size: 0.72rem;
  cursor: pointer;
}

.preset-row button:hover,
.preset-row button:focus-visible,
.preset-row button[aria-pressed="true"] {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--white);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  border: 1px solid var(--ink);
  border-radius: 6px;
  background: transparent;
  color: var(--ink);
  font-size: 0.82rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
}

.button--primary {
  border-color: var(--red);
  background: var(--red);
  color: var(--white);
}

.button--primary:hover,
.button--primary:focus-visible {
  border-color: var(--red-dark);
  background: var(--red-dark);
}

.button--ghost:hover,
.button--ghost:focus-visible {
  background: rgba(23, 32, 25, 0.08);
}

.button[aria-pressed="true"] {
  border-color: var(--red);
  color: var(--red);
}

.button:disabled {
  opacity: 0.42;
  cursor: not-allowed;
}

#cutButton {
  width: 100%;
}

.lab-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 18px;
}

.text-button {
  justify-self: start;
  min-height: 36px;
  margin-top: 10px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 0.7rem;
  text-decoration: underline;
  text-underline-offset: 4px;
  cursor: pointer;
}

.text-button:hover,
.text-button:focus-visible {
  color: var(--red);
}

.text-button:disabled {
  opacity: 0.34;
  cursor: not-allowed;
}

.milestones {
  display: grid;
  gap: 0;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.milestones li {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 11px 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}

.milestones li strong {
  font-weight: 500;
}

.milestones li.is-current {
  color: var(--red);
}

.lab-principle {
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.72rem;
}

.lab-principle summary {
  color: var(--ink);
  cursor: pointer;
  font-weight: 600;
}

.lab-principle summary::marker {
  color: var(--red);
}

.lab-principle div {
  padding-top: 10px;
}

.lab-principle p {
  margin: 0;
}

.formula {
  color: var(--red);
  font-family: "Songti SC", "SimSun", serif;
  white-space: nowrap;
}

.lab-note {
  margin-top: 20px;
}

.lab-reflection {
  max-width: 760px;
  margin: 56px 0 0 auto;
  padding: 4px 0 4px 24px;
  border-left: 2px solid var(--red);
}

.lab-reflection p {
  margin: 0;
  color: var(--ink-soft);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.15rem;
  line-height: 1.9;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0;
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.result-block {
  display: grid;
  align-content: start;
  min-height: 390px;
  padding: 42px 44px 42px 0;
}

.result-block + .result-block {
  padding-left: 44px;
  border-left: 1px solid var(--line-dark);
}

.result-block__meta {
  color: rgba(245, 247, 241, 0.52);
  font-size: 0.75rem;
}

.result-block strong {
  margin: 38px 0 8px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 6rem;
  font-weight: 400;
  line-height: 0.95;
  font-variant-numeric: tabular-nums;
}

.result-block__fraction {
  color: var(--red);
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
}

.result-block p {
  max-width: 30ch;
  margin: 36px 0 0;
  color: rgba(245, 247, 241, 0.64);
  font-size: 0.86rem;
}

.quote {
  max-width: 900px;
  margin: 96px 0 0 auto;
  padding: 0;
}

.quote p {
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 2.7rem;
  line-height: 1.52;
}

.quote cite {
  display: block;
  margin-top: 28px;
  color: rgba(245, 247, 241, 0.48);
  font-size: 0.74rem;
  font-style: normal;
}

.quote-note {
  max-width: 720px;
  margin: 32px 0 0 auto;
  color: rgba(245, 247, 241, 0.56);
  font-size: 0.86rem;
  line-height: 1.9;
}

.legacy-lead {
  max-width: 74ch;
  margin: -18px 0 48px;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.95;
}

.contribution-compare {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-bottom: 48px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.contribution-card {
  padding: 28px 32px 32px 0;
}

.contribution-card + .contribution-card {
  padding-right: 0;
  padding-left: 32px;
  border-left: 1px solid var(--line);
}

.contribution-card__label {
  margin: 0 0 16px;
  color: var(--red);
  font-size: 0.67rem;
  letter-spacing: 0.1em;
}

.contribution-card h3 {
  margin: 0 0 14px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.55rem;
  font-weight: 500;
  line-height: 1.5;
}

.contribution-card p:not(.contribution-card__label) {
  max-width: 52ch;
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.85;
}

.contribution-card p:last-child {
  margin-bottom: 0;
}

.contribution-card--modern .contribution-card__label {
  color: var(--jade);
}

.legacy-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.legacy-item {
  padding: 26px 28px 34px 0;
}

.legacy-item + .legacy-item {
  padding-left: 28px;
  border-left: 1px solid var(--line);
}

.legacy-item__meta {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  color: var(--muted);
  font-size: 0.68rem;
}

.legacy-item__meta span:first-child {
  color: var(--red);
}

.diagram {
  width: 100%;
  height: 220px;
  margin: 30px 0;
  color: var(--ink);
}

.three-figure {
  position: relative;
  height: 240px;
  margin: 30px 0;
  overflow: hidden;
  border-radius: var(--radius);
  background:
    linear-gradient(rgba(245, 247, 241, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 247, 241, 0.04) 1px, transparent 1px),
    #17211c;
  background-size: 28px 28px;
  cursor: grab;
  touch-action: pan-y;
}

.three-figure:active {
  cursor: grabbing;
}

.three-figure canvas {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
}

.three-figure .diagram {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 12px;
  color: rgba(245, 247, 241, 0.7);
}

.three-figure.has-three .three-figure__fallback {
  display: none;
}

.three-figure:focus-within {
  outline: 2px solid var(--red);
  outline-offset: 3px;
}

.diagram rect,
.diagram ellipse,
.diagram path,
.diagram line {
  fill: none;
  stroke: currentColor;
  stroke-width: 1;
  opacity: 0.42;
}

.diagram .diagram__accent {
  stroke: var(--red);
  opacity: 0.84;
}

.diagram circle {
  fill: var(--red);
}

.legacy-item h3 {
  margin: 0 0 12px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.5rem;
  font-weight: 500;
}

.legacy-item p {
  max-width: 28ch;
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
}

.star-field {
  position: absolute;
  inset: 0;
  z-index: 1;
  opacity: 0.72;
  background-image:
    radial-gradient(circle at 12% 18%, rgba(245, 247, 241, 0.78) 0 1px, transparent 1.4px),
    radial-gradient(circle at 28% 72%, rgba(245, 247, 241, 0.54) 0 1px, transparent 1.4px),
    radial-gradient(circle at 42% 28%, rgba(245, 247, 241, 0.42) 0 1px, transparent 1.4px),
    radial-gradient(circle at 62% 12%, rgba(245, 247, 241, 0.72) 0 1px, transparent 1.4px),
    radial-gradient(circle at 72% 54%, rgba(245, 247, 241, 0.6) 0 1px, transparent 1.4px),
    radial-gradient(circle at 86% 82%, rgba(245, 247, 241, 0.72) 0 1px, transparent 1.4px),
    radial-gradient(circle at 91% 35%, rgba(245, 247, 241, 0.5) 0 1px, transparent 1.4px),
    radial-gradient(circle at 18% 88%, rgba(245, 247, 241, 0.48) 0 1px, transparent 1.4px);
  background-size: 420px 420px;
}

.cosmos-art {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: right center;
  opacity: 0.62;
  pointer-events: none;
}

.cosmos-shell {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(360px, 1.1fr);
  grid-template-rows: auto auto;
  align-items: center;
  gap: 72px;
}

.cosmos-copy {
  position: relative;
  z-index: 2;
}

.cosmos-copy h2 {
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 4.4rem;
  font-weight: 500;
  line-height: 1.15;
}

.cosmos-copy > p:not(.section-kicker) {
  max-width: 36ch;
  margin: 28px 0 0;
  color: rgba(245, 247, 241, 0.62);
}

.cosmos-copy > p + p {
  margin-top: 16px;
  color: rgba(245, 247, 241, 0.48);
}

.star-fact {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  align-items: center;
  gap: 24px;
  max-width: 480px;
  margin-top: 46px;
  padding-top: 24px;
  border-top: 1px solid var(--line-dark);
}

.star-fact span {
  color: var(--red);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 2.4rem;
  font-variant-numeric: tabular-nums;
}

.star-fact p {
  max-width: 38ch;
  margin: 0;
  color: rgba(245, 247, 241, 0.58);
  font-size: 0.78rem;
}

.orbit-graphic {
  position: relative;
  aspect-ratio: 1;
  color: rgba(245, 247, 241, 0.32);
}

.orbit-graphic__ring {
  position: absolute;
  border: 1px solid currentColor;
  border-radius: 50%;
}

.orbit-graphic__ring--outer {
  inset: 0;
}

.orbit-graphic__ring--inner {
  inset: 19%;
  border-style: dashed;
}

.orbit-graphic__planet {
  position: absolute;
  top: 50%;
  left: 50%;
  display: grid;
  place-items: center;
  width: 40%;
  aspect-ratio: 1;
  border: 1px solid rgba(180, 60, 46, 0.8);
  border-radius: 50%;
  background: #18221d;
  color: var(--white);
  transform: translate(-50%, -50%);
}

.orbit-graphic__planet span {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.5rem;
}

.orbit-graphic__planet strong {
  color: var(--red);
  font-size: 0.72rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

.orbit-graphic__marker {
  position: absolute;
  top: 17%;
  left: 86%;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--red);
  box-shadow: 0 0 0 7px rgba(180, 60, 46, 0.12);
}

.cosmos-closing {
  grid-column: 1 / -1;
  margin: 42px 0 0;
  color: rgba(245, 247, 241, 0.54);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.2rem;
  line-height: 1.9;
  text-align: right;
}

.share-section {
  position: relative;
  overflow: hidden;
  padding: 112px 0 40px;
  background: var(--paper);
}

.share-art {
  position: absolute;
  right: -9%;
  bottom: -20%;
  width: min(72vw, 920px);
  opacity: 0.09;
  pointer-events: none;
}

.share-shell {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 0.78fr);
  gap: 28px 72px;
  align-items: end;
}

.share-copy h2 {
  max-width: 13ch;
  margin: 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 3.6rem;
  font-weight: 500;
  line-height: 1.2;
}

.share-copy > p:not(.section-kicker) {
  max-width: 42ch;
  margin: 24px 0 0;
  color: var(--muted);
}

.share-copy > p + p {
  margin-top: 14px;
}

.share-result {
  display: grid;
  gap: 20px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.share-result div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 20px;
}

.share-result span {
  color: var(--muted);
  font-size: 0.74rem;
}

.share-result strong {
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.6rem;
  font-weight: 500;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.share-actions {
  display: flex;
  grid-column: 1 / -1;
  gap: 10px;
  margin-top: 18px;
}

.experiment-summary {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  grid-column: 1 / -1;
  gap: 28px 44px;
  margin-top: 46px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.experiment-summary__result .section-kicker {
  margin-bottom: 12px;
}

.experiment-summary__result > p:last-child {
  max-width: 46ch;
  margin: 0;
  color: var(--ink-soft);
  font-size: 1rem;
  line-height: 1.9;
}

.experiment-summary__result strong {
  color: var(--red);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.25rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

.experiment-summary__question {
  align-self: center;
  padding-left: 26px;
  border-left: 1px solid var(--line);
}

.experiment-summary__question span {
  color: var(--red);
  font-size: 0.67rem;
  letter-spacing: 0.1em;
}

.experiment-summary__question p {
  max-width: 24ch;
  margin: 10px 0 0;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.25rem;
  line-height: 1.7;
}

.learning-path {
  display: flex;
  flex-wrap: wrap;
  grid-column: 1 / -1;
  gap: 8px 14px;
  margin: 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.72rem;
}

.learning-path span {
  color: var(--red);
}

.closing-thought {
  display: grid;
  grid-column: 1 / -1;
  gap: 8px;
  margin-top: 72px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.closing-thought__line {
  max-width: 68ch;
  margin: 0;
  color: var(--ink-soft);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.55rem;
  line-height: 1.7;
}

.closing-thought__quote {
  margin: 18px 0 0 auto;
  color: var(--red);
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.15rem;
  text-align: right;
}

.back-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 160;
  padding: 10px 14px;
  border: 1px solid rgba(23, 32, 25, 0.18);
  border-radius: 6px;
  background: rgba(238, 241, 235, 0.9);
  color: var(--ink);
  font-size: 0.72rem;
  text-decoration: none;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition:
    opacity 240ms var(--ease),
    transform 240ms var(--ease);
}

.sound-toggle {
  position: fixed;
  bottom: 24px;
  left: 24px;
  z-index: 190;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 40px;
  padding: 0 14px;
  border: 1px solid rgba(23, 32, 25, 0.18);
  border-radius: 6px;
  background: rgba(238, 241, 235, 0.9);
  color: var(--ink);
  font-size: 0.7rem;
  cursor: pointer;
  backdrop-filter: blur(10px);
}

.sound-toggle:hover,
.sound-toggle:focus-visible {
  border-color: var(--red);
  color: var(--red);
}

.sound-toggle__bars {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  width: 16px;
  height: 14px;
}

.sound-toggle__bars i {
  display: block;
  width: 2px;
  height: 4px;
  background: currentColor;
  transform-origin: bottom;
  transition: height 220ms var(--ease);
}

.sound-toggle__bars i:nth-child(2) {
  height: 9px;
}

.sound-toggle__bars i:nth-child(3) {
  height: 6px;
}

.sound-toggle[aria-pressed="true"] .sound-toggle__bars i {
  animation: sound-wave 1.25s ease-in-out infinite alternate;
}

.sound-toggle[aria-pressed="true"] .sound-toggle__bars i:nth-child(2) {
  animation-delay: 160ms;
}

.sound-toggle[aria-pressed="true"] .sound-toggle__bars i:nth-child(3) {
  animation-delay: 320ms;
}

@keyframes sound-wave {
  0% {
    height: 4px;
  }
  100% {
    height: 13px;
  }
}

.back-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.share-dialog {
  width: min(calc(100% - 32px), 480px);
  max-height: calc(100svh - 32px);
  padding: 0;
  overflow: auto;
  border: 0;
  border-radius: var(--radius);
  background: transparent;
  color: var(--ink);
}

.share-dialog::backdrop {
  background: rgba(10, 17, 13, 0.78);
  backdrop-filter: blur(8px);
}

.share-dialog__inner {
  position: relative;
  padding: 42px 22px 22px;
  background: var(--paper);
}

.image-dialog {
  width: min(calc(100% - 24px), 1120px);
  max-height: calc(100svh - 24px);
  padding: 0;
  overflow: auto;
  border: 0;
  border-radius: var(--radius);
  background: var(--paper);
  color: var(--ink);
}

.image-dialog::backdrop {
  background: rgba(10, 17, 13, 0.86);
  backdrop-filter: blur(8px);
}

.image-dialog__inner {
  position: relative;
  padding: 54px 18px 18px;
}

.image-dialog__inner img {
  width: 100%;
  max-height: 78svh;
  object-fit: contain;
  background: #171b18;
}

.image-dialog__inner p {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 0.76rem;
}

.dialog-close {
  position: absolute;
  top: 12px;
  right: 12px;
  min-height: 36px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  font-size: 0.72rem;
  cursor: pointer;
}

.share-card {
  position: relative;
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 380px;
  aspect-ratio: 3 / 4;
  margin: 0 auto;
  padding: 22px;
  overflow: hidden;
  border-radius: var(--radius);
  background:
    linear-gradient(rgba(245, 247, 241, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 247, 241, 0.04) 1px, transparent 1px),
    var(--night);
  background-size: 34px 34px;
  color: var(--white);
}

.share-card__top,
.share-card__bottom {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  color: rgba(245, 247, 241, 0.48);
  font-size: 0.62rem;
}

.share-card__graphic {
  position: relative;
  width: 70%;
  margin: 6% auto 2%;
}

.share-card__graphic svg {
  width: 100%;
  height: auto;
}

.share-card__graphic circle,
.share-card__graphic polygon,
.share-card__graphic line {
  fill: none;
  stroke: rgba(245, 247, 241, 0.52);
  stroke-width: 1;
}

.share-card__graphic polygon,
.share-card__graphic line {
  stroke: var(--red);
  stroke-width: 1.4;
}

.share-card__graphic circle:last-of-type {
  fill: var(--white);
  stroke: none;
}

.share-card__label {
  margin: 0;
  color: rgba(245, 247, 241, 0.46);
  font-size: 0.68rem;
}

.share-card__sides {
  margin-top: 2px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 2.6rem;
  font-weight: 500;
  line-height: 1.2;
}

.share-card__pi {
  margin: 0;
  color: var(--red);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
}

.share-card__quote {
  margin: auto 0 12px;
  font-family: "Songti SC", "SimSun", serif;
  font-size: 1.2rem;
}

.share-card__bottom {
  padding-top: 10px;
  border-top: 1px solid rgba(245, 247, 241, 0.16);
}

.share-dialog__actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 14px;
}

.share-status {
  min-height: 1.4em;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.72rem;
  text-align: center;
}

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity 700ms var(--ease),
    transform 700ms var(--ease);
}

.reveal.in-view {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 1020px) {
  .hero h1 {
    font-size: 6rem;
  }

  .hero__figure {
    width: min(62vw, 620px);
    right: -2vw;
  }

  .hero__figure--art {
    width: min(72vw, 780px);
    right: -12vw;
  }

  .problem-grid,
  .lab-shell,
  .cosmos-shell,
  .share-shell {
    grid-template-columns: 1fr;
  }

  .problem-grid {
    gap: 48px;
  }

  .media-slot--portrait {
    min-height: 430px;
  }

  .lab-stage {
    min-height: 540px;
  }

  .lab-controls {
    padding: 34px;
  }

  .cosmos-shell {
    gap: 48px;
  }

  .orbit-graphic {
    width: min(100%, 560px);
  }

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

  .culture-item,
  .culture-item + .culture-item {
    padding: 28px 26px 30px 0;
    border-left: 0;
  }

  .culture-item:nth-child(even) {
    padding-right: 0;
    padding-left: 26px;
  }

  .culture-item:nth-child(odd) {
    border-right: 1px solid rgba(245, 247, 241, 0.18);
  }

  .culture-item:nth-child(n + 3) {
    border-top: 1px solid rgba(245, 247, 241, 0.18);
  }

  .cosmos-closing {
    text-align: left;
  }

  .culture-pullquote {
    font-size: 2.2rem;
  }

  .polygon-compare__intro {
    gap: 24px;
  }

  .contribution-card {
    padding-right: 24px;
  }

  .contribution-card + .contribution-card {
    padding-left: 24px;
  }

  .closing-thought__line {
    font-size: 1.35rem;
  }

  .share-result {
    max-width: 520px;
  }
}

@media (max-width: 760px) {
  :root {
    --header-height: 62px;
  }

  body {
    font-size: 15px;
  }

  .site-header {
    padding: 0 18px;
  }

  .brand {
    gap: 10px;
  }

  .brand span {
    font-size: 1rem;
  }

  .brand small {
    display: none;
  }

  .chapter-rail {
    display: none;
  }

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

  .hero {
    padding-top: calc(var(--header-height) + 22px);
  }

  .hero__content {
    padding-top: 5vh;
  }

  .hero h1 {
    font-size: 4.5rem;
  }

  .hero__dek {
    max-width: 30ch;
    margin-top: 24px;
    font-size: 0.94rem;
  }

  .hero__manifesto {
    max-width: 31ch;
    font-size: 0.84rem;
  }

  .hero__cue {
    margin-top: 32px;
  }

  .hero__keywords {
    margin-top: 26px;
  }

  .hero__figure {
    right: -30%;
    bottom: 6vh;
    width: 112vw;
    opacity: 0.68;
  }

  .hero__figure--art {
    right: -64%;
    bottom: 2vh;
    width: 144vw;
    opacity: 0.48;
  }

  .hero__figure-label,
  .hero__side-note {
    display: none;
  }

  .chapter--paper,
  .chapter--lab,
  .chapter--culture,
  .chapter--dark,
  .chapter--night {
    padding: 84px 0;
  }

  .section-heading {
    margin-bottom: 42px;
  }

  .section-heading h2 {
    font-size: 2.7rem;
  }

  .culture-lead,
  .legacy-lead {
    margin-top: -10px;
    font-size: 0.86rem;
  }

  .chapter-bridge {
    grid-template-columns: 1fr;
    gap: 16px;
    margin-bottom: 32px;
    padding: 20px 0;
  }

  .chapter-bridge p {
    font-size: 0.94rem;
  }

  .polygon-compare {
    gap: 22px;
    margin-bottom: 32px;
    padding: 22px 0 26px;
  }

  .polygon-compare__intro {
    grid-template-columns: 1fr;
    grid-template-areas:
      "kicker"
      "title"
      "copy";
    gap: 10px;
  }

  .polygon-compare__intro h3 {
    font-size: 1.65rem;
  }

  .polygon-compare__intro > p:last-child {
    font-size: 0.88rem;
  }

  .polygon-compare__grid {
    gap: 6px;
  }

  .compare-figure {
    padding: 7px 7px 10px;
  }

  .compare-figure figcaption {
    display: grid;
    gap: 2px;
    margin-top: 4px;
    padding-top: 7px;
    font-size: 0.6rem;
  }

  .formula-line {
    font-size: 1.45rem !important;
  }

  .problem-copy .lead {
    font-size: 1.25rem;
  }

  .fact-list {
    grid-template-columns: 1fr;
    gap: 14px;
    margin-top: 36px;
  }

  .media-slot,
  .media-slot--portrait,
  .media-slot--wide {
    min-height: 340px;
    margin-top: 48px;
  }

  .media-slot__graphic {
    width: 128px;
    height: 128px;
  }

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

  .culture-item,
  .culture-item + .culture-item,
  .culture-item:nth-child(even) {
    padding: 28px 0 32px;
    border-left: 0;
    border-right: 0;
  }

  .culture-item:nth-child(n + 2) {
    border-top: 1px solid rgba(245, 247, 241, 0.18);
  }

  .culture-item__visual {
    aspect-ratio: 420 / 240;
  }

  .culture-item h3 {
    font-size: 1.45rem;
  }

  .culture-item .culture-modern {
    font-size: 0.7rem;
  }

  .culture-pullquote {
    margin-top: 64px;
    font-size: 1.9rem;
    text-align: left;
  }

  .culture-note {
    display: grid;
    gap: 8px;
    margin-top: 42px;
  }

  .archive-image--wide {
    margin-top: 48px;
  }

  .archive-image--document {
    margin-top: 48px;
    padding: 10px;
  }

  .lab-shell {
    margin-inline: -18px;
    border-right: 0;
    border-left: 0;
    border-radius: 0;
  }

  .lab-stage {
    min-height: 430px;
    padding: 26px 22px;
  }

  .lab-stage::before {
    inset: 12px;
  }

  .lab-controls {
    padding: 28px 20px 32px;
  }

  .lab-readout strong {
    font-size: 1.35rem;
  }

  .lab-reflection {
    margin-top: 40px;
    padding-left: 18px;
  }

  .lab-reflection p {
    font-size: 1rem;
  }

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

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

  .result-block {
    min-height: auto;
    padding: 32px 0;
  }

  .result-block + .result-block {
    padding-left: 0;
    border-top: 1px solid var(--line-dark);
    border-left: 0;
  }

  .result-block strong {
    margin-top: 24px;
    font-size: 4.2rem;
  }

  .quote {
    margin-top: 62px;
  }

  .quote p {
    font-size: 1.8rem;
  }

  .quote-note {
    margin-top: 24px;
    font-size: 0.8rem;
  }

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

  .legacy-item,
  .legacy-item + .legacy-item {
    padding: 28px 0 34px;
    border-left: 0;
  }

  .legacy-item + .legacy-item {
    border-top: 1px solid var(--line);
  }

  .diagram {
    height: 180px;
    margin: 22px 0;
  }

  .three-figure {
    height: 210px;
    margin: 24px 0;
  }

  .contribution-compare {
    grid-template-columns: 1fr;
    margin-bottom: 34px;
  }

  .contribution-card,
  .contribution-card + .contribution-card {
    padding: 24px 0 28px;
    border-left: 0;
  }

  .contribution-card + .contribution-card {
    border-top: 1px solid var(--line);
  }

  .contribution-card h3 {
    font-size: 1.35rem;
  }

  .chapter--night {
    min-height: auto;
  }

  .cosmos-copy h2 {
    font-size: 3rem;
  }

  .cosmos-art {
    opacity: 0.45;
  }

  .star-fact {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .orbit-graphic {
    width: min(100%, 430px);
  }

  .orbit-graphic__planet span {
    font-size: 1.1rem;
  }

  .share-section {
    padding-top: 84px;
  }

  .share-copy h2 {
    font-size: 2.7rem;
  }

  .share-art {
    right: -48%;
    bottom: -10%;
    width: 150vw;
    opacity: 0.06;
  }

  .share-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .experiment-summary {
    grid-template-columns: 1fr;
    gap: 22px;
    margin-top: 36px;
    padding: 22px 0;
  }

  .experiment-summary__question {
    padding: 18px 0 0;
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .experiment-summary__question p {
    max-width: 30ch;
    font-size: 1.1rem;
  }

  .learning-path {
    gap: 6px 10px;
    font-size: 0.68rem;
  }

  .closing-thought {
    margin-top: 54px;
  }

  .closing-thought__line {
    font-size: 1.28rem;
  }

  .closing-thought__quote {
    font-size: 1rem;
  }

  .back-top {
    right: 14px;
    bottom: 14px;
  }

  .sound-toggle {
    bottom: 14px;
    left: 14px;
  }

  .share-dialog__inner {
    padding: 42px 14px 14px;
  }

  .share-dialog__actions {
    grid-template-columns: 1fr;
  }

  .image-dialog {
    width: calc(100% - 16px);
    max-height: calc(100svh - 16px);
  }

  .image-dialog__inner {
    padding: 50px 10px 10px;
  }

  .image-dialog__inner img {
    max-height: 68svh;
  }
}

@media (max-width: 390px) {
  .hero h1 {
    font-size: 4rem;
  }

  .section-heading h2,
  .cosmos-copy h2,
  .share-copy h2 {
    font-size: 2.35rem;
  }

  .result-block strong {
    font-size: 3.6rem;
  }

  .lab-stage {
    min-height: 360px;
  }
}

@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;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}