:root {
  --ink: #10151d;
  --ink-soft: #1b2430;
  --paper: #f3eee3;
  --paper-deep: #e7dfd0;
  --muted: #9da8b5;
  --coral: #ff7766;
  --cyan: #82e5dc;
  --lime: #d8ee75;
  --line: rgba(16, 21, 29, .18);
  --serif: Georgia, 'Times New Roman', serif;
  --sans: 'Avenir Next', Avenir, 'Helvetica Neue', Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--sans);
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); overflow-x: hidden; }
a { color: inherit; }
button, input { font: inherit; }
button { cursor: pointer; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 70px;
  padding: 0 5vw;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.wordmark { text-decoration: none; }
.wordmark span { color: #78818a; font-weight: 500; }
.language-link { text-decoration: none; border-bottom: 1px solid var(--ink); padding-bottom: 3px; }

.hero {
  display: grid;
  grid-template-columns: minmax(0, .96fr) minmax(360px, 1.04fr);
  min-height: 690px;
  background: var(--paper);
}
.hero-copy { align-self: center; padding: 8vw 7vw 8vw 10vw; position: relative; z-index: 2; }
.eyebrow { margin: 0 0 18px; color: #65707b; font-size: .68rem; font-weight: 800; letter-spacing: .19em; line-height: 1.4; }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 660px; margin-bottom: 26px; font-family: var(--serif); font-size: clamp(3.8rem, 7vw, 7.4rem); font-weight: 400; letter-spacing: -.065em; line-height: .9; }
h1 em { color: var(--coral); font-style: italic; }
.lead { max-width: 560px; margin-bottom: 42px; color: #3d4854; font-size: clamp(1.02rem, 1.55vw, 1.3rem); line-height: 1.55; }
.hero-fact { display: flex; align-items: center; gap: 20px; max-width: 510px; padding-top: 18px; border-top: 2px solid var(--ink); }
.hero-fact p { max-width: 280px; margin: 0; color: #59636e; font-size: .82rem; line-height: 1.35; }
.hero-number { font-family: var(--serif); font-size: clamp(3.1rem, 5vw, 5.2rem); letter-spacing: -.07em; line-height: .8; white-space: nowrap; }
.hero-number small { font-family: var(--sans); font-size: .28em; font-weight: 800; letter-spacing: .08em; }

.hero-art { position: relative; min-height: 690px; overflow: hidden; background: var(--ink-soft); }
.hero-art::before { content: ''; position: absolute; inset: 0; opacity: .23; background: repeating-linear-gradient(90deg, transparent 0 47px, rgba(130,229,220,.25) 48px 49px), repeating-linear-gradient(0deg, transparent 0 47px, rgba(130,229,220,.2) 48px 49px); }
.hero-art::after { content: ''; position: absolute; top: 0; bottom: 0; left: 50%; width: 1px; background: rgba(130,229,220,.24); }
.air-ring { position: absolute; left: 50%; top: 50%; border: 1px solid rgba(130,229,220,.55); border-radius: 50%; transform: translate(-50%, -50%); }
.ring-one { width: 63%; aspect-ratio: 1; }
.ring-two { width: 40%; aspect-ratio: 1; border-color: rgba(216,238,117,.55); }
.diaphragm { position: absolute; left: 12%; right: 52%; top: 55%; height: 160px; border-bottom: 6px solid var(--cyan); border-radius: 0 0 50% 50%; transform: rotate(-8deg); box-shadow: 0 16px 0 -10px rgba(130,229,220,.22); }
.diaphragm::before, .diaphragm::after { content: ''; position: absolute; bottom: -16px; width: 26px; height: 26px; border: 3px solid var(--cyan); border-radius: 50%; background: var(--ink-soft); }
.diaphragm::before { left: -8px; }
.diaphragm::after { right: -8px; }
.glottis { position: absolute; top: 31%; right: 18%; width: 126px; height: 190px; border: 2px solid var(--coral); border-radius: 65px 65px 15px 15px; transform: rotate(8deg); }
.glottis::before, .glottis::after, .glottis span { content: ''; position: absolute; left: 50%; width: 82px; height: 9px; border-radius: 9px; background: var(--coral); transform: translateX(-50%); }
.glottis::before { top: 61px; }
.glottis::after { top: 99px; }
.glottis span { top: 80px; height: 2px; background: rgba(255,119,102,.35); }
.air-pulse { position: absolute; left: 21%; top: 49%; width: 300px; height: 2px; background: linear-gradient(90deg, transparent, var(--lime), transparent); transform: rotate(-10deg); box-shadow: 0 0 20px var(--lime); }
.air-pulse::before, .air-pulse::after { content: ''; position: absolute; width: 10px; height: 10px; border-top: 2px solid var(--lime); border-right: 2px solid var(--lime); transform: rotate(45deg); }
.air-pulse::before { left: 30%; top: -4px; }
.air-pulse::after { left: 70%; top: -4px; }
.art-label { position: absolute; margin: 0; color: var(--cyan); font-size: .64rem; font-weight: 800; letter-spacing: .14em; }
.label-diaphragm { left: 11%; bottom: 24%; }
.label-glottis { right: 14%; top: 25%; color: var(--coral); }
.art-caption { position: absolute; right: 9%; bottom: 13%; margin: 0; color: var(--lime); font-family: var(--serif); font-size: 1.25rem; font-style: italic; line-height: 1.05; text-align: right; }

.section { padding: 110px 10vw; }
.section-dark { color: #f5f1e7; background: var(--ink); }
.section-paper { background: var(--paper); }
.section-split { background: var(--paper-deep); }
.section-intro { max-width: 790px; margin-bottom: 55px; }
.section-intro.narrow { max-width: 650px; }
.section h2 { max-width: 790px; margin-bottom: 22px; font-family: var(--serif); font-size: clamp(2.8rem, 5.2vw, 5.5rem); font-weight: 400; letter-spacing: -.055em; line-height: .94; }
.section-intro > p:not(.eyebrow) { max-width: 650px; color: #aeb7c0; font-size: 1.03rem; line-height: 1.58; }
.section-paper .section-intro > p:not(.eyebrow), .section-split .section-intro > p:not(.eyebrow) { color: #53606b; }

.instrument-panel { display: grid; grid-template-columns: minmax(0, 1.5fr) minmax(250px, .5fr); gap: 24px; }
.canvas-wrap { min-width: 0; padding: 25px 25px 18px; border: 1px solid rgba(130,229,220,.35); background: #141e29; }
canvas { display: block; width: 100%; height: auto; }
.canvas-legend { display: flex; flex-wrap: wrap; gap: 18px; padding-top: 13px; color: #aeb7c0; font-size: .75rem; }
.canvas-legend span { display: inline-flex; align-items: center; gap: 7px; }
.canvas-legend i { display: inline-block; width: 17px; height: 3px; border-radius: 5px; background: var(--cyan); }
.canvas-legend .legend-glottis { background: var(--coral); }
.canvas-legend .legend-air { background: var(--lime); }
.controls { display: flex; flex-direction: column; gap: 23px; padding: 25px; border: 1px solid rgba(130,229,220,.35); background: #141e29; }
.controls label { display: grid; gap: 11px; color: #f5f1e7; font-size: .8rem; font-weight: 700; }
.controls label > span { display: flex; justify-content: space-between; gap: 10px; }
.controls output { color: var(--lime); white-space: nowrap; }
.controls small { color: #8995a0; font-size: .72rem; font-weight: 400; line-height: 1.35; }
input[type=range] { width: 100%; accent-color: var(--coral); }
.metric-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.metric { padding: 13px; border-top: 2px solid var(--cyan); background: rgba(130,229,220,.07); }
.metric:nth-child(2) { border-color: var(--coral); }
.metric span { display: block; min-height: 33px; color: #aeb7c0; font-size: .68rem; line-height: 1.25; }
.metric strong { display: block; margin-top: 8px; color: var(--lime); font-family: var(--serif); font-size: 1.75rem; font-weight: 400; letter-spacing: -.04em; }
.model-result { margin: 0; color: var(--cyan); font-size: .88rem; line-height: 1.45; }
.model-note { margin: auto 0 0; padding-top: 18px; border-top: 1px solid rgba(245,241,231,.18); color: #8995a0; font-size: .74rem; line-height: 1.4; }
.model-note strong { color: #f5f1e7; }
.equation { margin: 35px 0 0; color: var(--lime); font-family: var(--serif); font-size: 1.7rem; }

.safety-note { max-width: 830px; margin: -12px 0 32px; padding: 17px 20px; border-left: 4px solid var(--coral); background: rgba(255,119,102,.1); color: #4e3c38; font-size: .89rem; line-height: 1.5; }
.safety-note strong { color: #a9463b; }
.counter-panel { display: grid; grid-template-columns: 210px minmax(230px, 1fr) 220px; gap: 24px; align-items: center; max-width: 980px; padding: 30px; border: 1px solid var(--line); background: #ece4d6; }
.timer-face { display: flex; flex-direction: column; align-items: center; justify-content: center; width: 170px; height: 170px; border: 8px solid var(--coral); border-radius: 50%; background: var(--ink); color: var(--lime); box-shadow: 0 0 0 5px #ece4d6, 0 0 0 6px var(--coral); }
.timer-face span { font-family: var(--serif); font-size: 3rem; letter-spacing: -.08em; line-height: 1; }
.timer-face small { color: #d9d2c7; font-size: .68rem; text-transform: uppercase; letter-spacing: .12em; }
.counter-controls { display: grid; gap: 11px; }
.action-button { min-height: 47px; padding: 11px 16px; border: 2px solid var(--ink); background: var(--coral); color: var(--ink); font-weight: 800; text-align: left; }
.action-button:hover, .action-button:focus-visible { background: var(--lime); }
.action-button.secondary { background: transparent; }
.action-button:disabled { cursor: not-allowed; opacity: .42; }
.counter-controls p { margin: 3px 0 0; color: #64707b; font-size: .8rem; }
.count-result { padding-left: 20px; border-left: 1px solid var(--line); }
.count-result span, .count-result small { display: block; color: #68747d; font-size: .72rem; line-height: 1.4; }
.count-result strong { display: block; margin: 6px 0; font-family: var(--serif); font-size: 4.2rem; font-weight: 400; letter-spacing: -.08em; line-height: .9; }
.small-print { max-width: 760px; margin: 20px 0 0; color: #74808a; font-size: .76rem; }

.mechanism-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border-top: 1px solid var(--line); }
.mechanism-list article { min-height: 265px; padding: 26px 28px 25px 0; border-right: 1px solid var(--line); }
.mechanism-list article + article { padding-left: 28px; }
.mechanism-list article:last-child { border-right: 0; }
.step-number { display: inline-block; margin-bottom: 55px; color: var(--coral); font-size: .72rem; font-weight: 800; letter-spacing: .14em; }
.mechanism-list h3 { margin-bottom: 12px; font-family: var(--serif); font-size: 1.7rem; font-weight: 400; letter-spacing: -.04em; }
.mechanism-list p { max-width: 290px; margin: 0; color: #59656e; font-size: .88rem; line-height: 1.55; }

.fact-section { padding-bottom: 80px; }
.fact-layout { display: grid; grid-template-columns: .9fr 1.1fr; gap: 9vw; align-items: end; }
.fact-layout h2 { font-size: clamp(2.8rem, 5vw, 5.4rem); }
.study-card { padding: 30px; border: 1px solid rgba(216,238,117,.5); background: #151f29; }
.study-big { margin-bottom: 18px; color: var(--lime); font-family: var(--serif); font-size: clamp(4.6rem, 9vw, 9rem); letter-spacing: -.1em; line-height: .8; }
.study-big span { color: var(--cyan); font-family: var(--sans); font-size: .18em; font-weight: 800; letter-spacing: .1em; }
.study-card p:not(.study-big) { max-width: 560px; margin-bottom: 26px; color: #e7e3d9; font-size: .98rem; line-height: 1.55; }
.study-card small { display: block; color: #9da8b5; font-size: .76rem; line-height: 1.5; }
.method-note { max-width: 810px; margin: 70px 0 0; padding-top: 18px; border-top: 1px solid rgba(245,241,231,.18); color: #aeb7c0; font-size: .82rem; line-height: 1.55; }
.method-note strong { color: #f5f1e7; }

.sources-section { padding-bottom: 130px; }
.source-list { max-width: 930px; margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.source-list li { display: grid; grid-template-columns: 55px 1fr; gap: 22px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.source-index { color: var(--coral); font-size: .72rem; font-weight: 800; }
.source-list cite { display: block; max-width: 670px; margin-bottom: 8px; font-family: var(--serif); font-size: 1.35rem; font-style: normal; letter-spacing: -.02em; line-height: 1.15; }
.source-list a { color: #656f78; font-size: .76rem; font-weight: 700; }
.site-footer { padding: 25px 5vw; background: var(--ink); color: #aeb7c0; font-size: .72rem; }
.footer-line { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.footer-line a:first-child { color: #f5f1e7; font-weight: 800; text-decoration: none; }
.footer-line a:last-child { color: var(--lime); text-decoration: none; }

:focus-visible { outline: 3px solid var(--coral); outline-offset: 3px; }
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; }
  .hero-copy { padding: 80px 8vw 60px; }
  .hero-art { min-height: 480px; }
  .instrument-panel { grid-template-columns: 1fr; }
  .counter-panel { grid-template-columns: 180px 1fr; }
  .count-result { grid-column: 1 / -1; padding: 18px 0 0; border-top: 1px solid var(--line); border-left: 0; }
  .fact-layout { grid-template-columns: 1fr; gap: 35px; }
}
@media (max-width: 620px) {
  .site-header { min-height: 58px; padding: 0 5vw; font-size: .61rem; }
  .wordmark span { display: none; }
  .hero-copy { padding: 65px 6vw 52px; }
  h1 { font-size: clamp(3.2rem, 16vw, 5rem); }
  .lead { font-size: 1rem; }
  .hero-fact { align-items: flex-start; gap: 13px; }
  .hero-number { font-size: 3.4rem; }
  .hero-fact p { font-size: .75rem; }
  .hero-art { min-height: 360px; }
  .ring-one { width: 90%; }
  .ring-two { width: 57%; }
  .diaphragm { left: 7%; right: 48%; top: 53%; height: 90px; }
  .glottis { right: 8%; top: 22%; transform: scale(.72) rotate(8deg); transform-origin: top right; }
  .air-pulse { left: 10%; top: 49%; width: 240px; }
  .label-diaphragm { left: 7%; bottom: 20%; }
  .label-glottis { right: 7%; top: 17%; }
  .art-caption { right: 8%; bottom: 9%; font-size: 1rem; }
  .section { padding: 75px 6vw; }
  .section h2 { font-size: clamp(2.6rem, 12vw, 4.4rem); }
  .section-intro { margin-bottom: 38px; }
  .canvas-wrap, .controls { padding: 14px; }
  .canvas-legend { gap: 10px; font-size: .66rem; }
  .metric strong { font-size: 1.45rem; }
  .counter-panel { grid-template-columns: 1fr; justify-items: center; padding: 21px; }
  .counter-controls, .count-result { width: 100%; }
  .counter-controls { justify-items: stretch; }
  .count-result { text-align: center; }
  .mechanism-list { grid-template-columns: 1fr; }
  .mechanism-list article, .mechanism-list article + article { min-height: 0; padding: 22px 0; border-right: 0; border-bottom: 1px solid var(--line); }
  .mechanism-list article:last-child { border-bottom: 0; }
  .step-number { margin-bottom: 24px; }
  .study-card { padding: 21px; }
  .study-big { font-size: 5.3rem; }
  .source-list li { grid-template-columns: 34px 1fr; gap: 9px; }
  .source-list cite { font-size: 1.1rem; }
  .footer-line { align-items: flex-start; flex-direction: column; gap: 8px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}