:root {
  --ink: #11100e;
  --paper: #f2efe7;
  --cream: #e8e3d8;
  --orange: #ff5c35;
  --orange-soft: #ffb39e;
  --cyan: #78e7e3;
  --muted: #6f6a60;
  --line: rgba(17, 16, 14, 0.17);
  --serif: "Songti SC", "STSong", "Noto Serif CJK SC", Georgia, serif;
  --sans: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--ink); }
body { margin: 0; background: var(--paper); color: var(--ink); font-family: var(--sans); }
button, input { font: inherit; }
a { color: inherit; text-decoration: none; }
::selection { background: var(--orange); color: white; }

.progress { position: fixed; z-index: 100; left: 0; top: 0; height: 3px; background: var(--orange); transition: width .1s linear; }
.nav-shell { position: fixed; z-index: 90; top: 22px; left: 50%; transform: translateX(-50%); width: min(1120px, calc(100% - 36px)); height: 62px; padding: 0 10px 0 16px; display: flex; align-items: center; justify-content: space-between; border: 1px solid rgba(255,255,255,.16); background: rgba(17,16,14,.82); backdrop-filter: blur(18px); color: white; border-radius: 7px; }
.brand { display: flex; align-items: center; gap: 10px; font-size: 12px; letter-spacing: .14em; font-weight: 800; }
.brand-mark { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; background: var(--orange); color: white; font-family: Georgia, serif; font-size: 20px; font-style: italic; letter-spacing: 0; }
.nav-links { display: flex; align-items: center; gap: 6px; }
.nav-links a { color: #d9d5cc; padding: 12px 14px; font-size: 13px; border-radius: 4px; transition: .2s; }
.nav-links a:hover { background: rgba(255,255,255,.08); color: white; }
.menu-button { display: none; color: white; background: none; border: 0; }

.hero { min-height: 940px; padding: 185px max(28px, calc((100vw - 1120px)/2)) 80px; background: var(--ink); color: white; position: relative; overflow: hidden; display: grid; grid-template-columns: 1.13fr .87fr; align-items: center; }
.hero-grid { position: absolute; inset: 0; opacity: .16; background-image: linear-gradient(rgba(255,255,255,.08) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.08) 1px, transparent 1px); background-size: 58px 58px; mask-image: linear-gradient(to bottom, black, transparent 82%); }
.hero::before { content: ""; position: absolute; width: 750px; height: 750px; right: -230px; top: 100px; border: 1px solid rgba(120,231,227,.16); border-radius: 50%; box-shadow: 0 0 0 100px rgba(120,231,227,.025), 0 0 0 200px rgba(120,231,227,.018); }
.hero-copy, .hero-art { position: relative; z-index: 2; }
.award-pill { display: inline-flex; align-items: center; gap: 10px; border: 1px solid rgba(255,255,255,.2); color: #d8d2c8; padding: 9px 13px; border-radius: 100px; font-size: 12px; }
.award-pill i { width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 16px var(--cyan); }
.kicker { margin: 48px 0 14px; color: var(--orange-soft); font-size: 12px; font-weight: 700; letter-spacing: .24em; text-transform: uppercase; }
.hero h1 { margin: 0; font-family: var(--serif); font-size: clamp(70px, 8.7vw, 132px); line-height: .9; letter-spacing: -.07em; font-weight: 600; }
.hero h1 em { color: var(--orange); font-style: normal; }
.hero-lead { max-width: 680px; margin: 35px 0 0; color: #bdb9b0; font-size: 18px; line-height: 1.9; }
.hero-actions { display: flex; align-items: center; gap: 24px; margin-top: 38px; }
.cta { display: inline-flex; align-items: center; gap: 30px; padding: 17px 20px; background: white; color: var(--ink); border-radius: 4px; font-size: 14px; font-weight: 700; transition: transform .2s, background .2s; }
.cta:hover { transform: translateY(-2px); background: var(--cyan); }
.cta span { color: var(--orange); font-size: 20px; }
.time-note { color: #77736c; font-size: 12px; }
.hero-art { height: 560px; min-width: 0; perspective: 900px; }
.hero-art .needle-cloud { left: 52%; top: 46%; }
.hero-art p { position: absolute; right: 2%; bottom: 5%; display: flex; align-items: center; gap: 12px; color: #aaa59c; font-size: 12px; line-height: 1.4; }
.hero-art p b { color: var(--cyan); font-family: Georgia, serif; font-size: 56px; font-weight: 400; }
.axis { position: absolute; z-index: 1; color: rgba(255,255,255,.28); font: italic 13px Georgia, serif; }
.axis::before { content: ""; display: block; position: absolute; background: rgba(255,255,255,.13); }
.axis.x { left: 7%; top: 52%; }.axis.x::before { width: 440px; height: 1px; left: 13px; top: 8px; transform: rotate(-7deg); transform-origin: left; }
.axis.y { left: 52%; top: 3%; }.axis.y::before { width: 1px; height: 460px; left: 3px; top: 18px; }
.axis.z { right: 13%; top: 18%; }.axis.z::before { width: 350px; height: 1px; right: 14px; top: 8px; transform: rotate(-45deg); transform-origin: right; }
.hero-footnote { position: absolute; z-index: 3; bottom: 38px; left: 50%; transform: translateX(-50%); width: min(1120px, calc(100% - 56px)); padding-top: 18px; border-top: 1px solid rgba(255,255,255,.11); color: #77736c; font-size: 12px; }

.needle-cloud { position: absolute; width: 460px; height: 460px; left: 50%; top: 50%; transform: translate(-50%,-50%) rotateX(60deg) rotateZ(-12deg); transform-style: preserve-3d; animation: cloudFloat 9s ease-in-out infinite; }
.needle-cloud i { position: absolute; left: 50%; top: 50%; width: 330px; height: 3px; border-radius: 3px; background: linear-gradient(90deg, transparent, var(--orange-soft) 18%, var(--orange) 52%, var(--cyan) 100%); transform-origin: 50% 50%; box-shadow: 0 0 8px rgba(255,92,53,.24); animation: rodPulse 3s ease-in-out infinite alternate; }
.needle-cloud i::after { content: ""; position: absolute; right: -1px; top: -2px; width: 7px; height: 7px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 12px var(--cyan); }
.cloud-core { position: absolute; left: 50%; top: 50%; width: 130px; height: 130px; transform: translate(-50%,-50%) translateZ(20px); border: 1px solid rgba(255,255,255,.18); border-radius: 50%; background: radial-gradient(circle, rgba(255,92,53,.2), transparent 68%); box-shadow: 0 0 70px rgba(255,92,53,.2); }
@keyframes cloudFloat { 50% { transform: translate(-50%,-52%) rotateX(64deg) rotateZ(-7deg); } }
@keyframes rodPulse { to { opacity: .65; filter: brightness(1.35); } }

.chapter { position: relative; padding: 130px max(28px, calc((100vw - 1120px)/2)); }
.chapter-number { position: absolute; top: 138px; left: max(28px, calc((100vw - 1260px)/2)); font-family: Georgia, serif; font-style: italic; color: var(--orange); font-size: 14px; }
.section-heading { margin-left: 95px; max-width: 760px; }
.section-heading.wide { max-width: 940px; }
.eyebrow { display: block; margin-bottom: 18px; color: var(--orange); font-size: 11px; font-weight: 800; letter-spacing: .2em; text-transform: uppercase; }
.section-heading h2, .sources-section h2 { margin: 0; font-family: var(--serif); font-size: clamp(44px, 5.15vw, 72px); font-weight: 600; line-height: 1.16; letter-spacing: -.04em; text-wrap: balance; }
.keep-together { white-space: nowrap; }
.section-heading > p { max-width: 760px; margin: 25px 0 0; color: var(--muted); font-size: 17px; line-height: 1.9; }

.definition-card { margin: 70px 0 0 95px; display: grid; grid-template-columns: 1.2fr .8fr; min-height: 260px; border: 1px solid var(--line); background: #faf8f3; }
.formula { display: flex; flex-direction: column; justify-content: center; gap: 20px; padding: 48px; border-right: 1px solid var(--line); font-family: var(--serif); font-size: clamp(24px, 2.45vw, 36px); line-height: 1.45; }
.formula i { color: var(--orange); font-family: Georgia, serif; }
.formula b { display: block; font-family: Georgia, serif; font-size: .92em; font-weight: 400; white-space: nowrap; }
.formula-translation { display: grid; grid-template-columns: 36px 1fr; gap: 22px 12px; align-content: center; padding: 40px; color: var(--muted); font-size: 14px; }
.formula-translation span { color: var(--orange); font-family: Georgia, serif; font-size: 22px; font-weight: 700; }
.correction { margin: 24px 0 0 95px; padding: 34px 40px; background: #dedad0; border-left: 4px solid var(--orange); }
.correction-title { display: flex; align-items: center; gap: 12px; font-weight: 800; }
.correction-title span { display: grid; place-items: center; width: 24px; height: 24px; border-radius: 50%; background: var(--ink); color: white; font-size: 13px; }
.correction-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 46px; margin-top: 28px; }
.correction-grid > div + div { border-left: 1px solid rgba(17,16,14,.18); padding-left: 46px; }
.correction small { color: var(--muted); font-size: 11px; letter-spacing: .14em; }
.correction p { margin: 8px 0 0; font-family: var(--serif); font-size: 22px; line-height: 1.6; }
.correction .fineprint { font-family: var(--sans); color: var(--muted); font-size: 12px; }
.plane-story { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 80px; margin-top: 110px; }
.plane-story h3 { font-family: var(--serif); font-size: 42px; line-height: 1.25; margin: 0 0 25px; text-wrap: balance; }
.plane-story p { color: var(--muted); line-height: 1.85; }
.callout-line { border-top: 1px solid var(--line); padding-top: 20px; color: var(--ink) !important; font-weight: 700; }
.plane-visual { position: relative; min-height: 440px; background-color: var(--ink); background-image: radial-gradient(rgba(255,255,255,.12) 1px, transparent 1px); background-size: 17px 17px; overflow: hidden; }
.plane-visual::after { content: "面积 → 0"; position: absolute; right: 18px; bottom: 16px; color: var(--cyan); font: italic 15px Georgia, serif; }
.plane-visual i { position: absolute; width: 78%; height: 2px; background: linear-gradient(90deg, transparent, var(--orange), transparent); transform-origin: center; opacity: .8; box-shadow: 0 0 6px var(--orange); }

.dimension-section { background: #dedad0; }
.measure-toggle { width: max-content; margin: 58px 0 0 95px; padding: 4px; display: flex; border: 1px solid var(--line); border-radius: 5px; }
.measure-toggle button { padding: 11px 24px; background: transparent; border: 0; color: var(--muted); cursor: pointer; }
.measure-toggle button.active { background: var(--ink); color: white; border-radius: 3px; }
.zero-vs-three { margin: 20px 0 0 95px; min-height: 310px; padding: 40px 55px 40px 30px; display: grid; grid-template-columns: 260px 1fr; align-items: center; background: var(--ink); color: white; overflow: hidden; position: relative; }
.zero-vs-three::after { content: ""; position: absolute; right: -90px; top: -140px; width: 400px; height: 400px; border: 1px solid rgba(120,231,227,.2); border-radius: 50%; }
.zero-symbol { font-family: Georgia, serif; font-size: 230px; line-height: .8; text-align: center; color: var(--orange); transition: .3s; }
.zero-vs-three.dimension .zero-symbol { color: var(--cyan); }
.zero-vs-three h3 { position: relative; z-index: 1; margin: 0 0 15px; max-width: 590px; font-family: var(--serif); font-size: 33px; }
.zero-vs-three p { position: relative; z-index: 1; max-width: 640px; color: #aaa59c; line-height: 1.8; }
.scale-lab { margin: 28px 0 0 95px; padding: 46px; background: var(--paper); border: 1px solid var(--line); }
.lab-controls { display: flex; justify-content: space-between; gap: 50px; align-items: flex-end; }
.lab-controls h3 { margin: 0; font-family: var(--serif); font-size: 34px; }
.lab-controls label { min-width: 320px; color: var(--muted); font-size: 12px; }
.lab-controls input { width: 100%; display: block; margin-top: 14px; accent-color: var(--orange); }
.dimension-stage { min-height: 430px; display: grid; grid-template-columns: 1.15fr .85fr; align-items: center; gap: 40px; perspective: 900px; }
.cube-wrap { position: relative; width: 265px; height: 265px; margin: auto; transform: rotateX(58deg) rotateZ(-38deg); transform-style: preserve-3d; }
.cube-face { position: absolute; inset: 0; border: 1px solid rgba(255,92,53,.7); background-color: rgba(255,92,53,.06); }
.cube-front { display: grid; grid-template-columns: repeat(var(--cells), 1fr); grid-template-rows: repeat(var(--cells), 1fr); }
.cube-front i { border: 1px solid rgba(255,92,53,.16); }
.cube-side { transform: rotateY(90deg) translateZ(132px) translateX(132px); background: rgba(120,231,227,.04); border-color: rgba(120,231,227,.5); }
.cube-top { transform: rotateX(90deg) translateZ(132px) translateY(-132px); background: rgba(255,255,255,.2); }
.cube-needles { position: absolute; inset: 0; transform: translateZ(30px); }
.cube-needles b { position: absolute; left: 3%; top: 50%; width: 94%; height: 3px; background: var(--ink); transform-origin: center; }
.count-readout { display: grid; grid-template-columns: 1fr; }
.count-readout p { margin: 14px 0 0; color: var(--muted); }
.count-readout strong { font: 55px Georgia, serif; line-height: 1.1; }
.count-readout .accent-number { color: var(--orange); }
.count-readout span { color: var(--muted); font-size: 12px; }
.lab-conclusion { margin: 0; padding-top: 24px; border-top: 1px solid var(--line); line-height: 1.75; }
.lab-conclusion b { color: var(--orange); }

.theorem-section { padding-top: 0; background: #dedad0; }
.theorem-card { padding: 75px 80px; background: var(--orange); color: var(--ink); }
.theorem-card .eyebrow { color: var(--ink); }
.theorem-card blockquote { margin: 0; max-width: 900px; font-family: var(--serif); font-size: clamp(38px, 5vw, 67px); line-height: 1.3; letter-spacing: -.035em; }
.theorem-punch { display: flex; align-items: center; gap: 16px; margin-top: 50px; padding-top: 30px; border-top: 1px solid rgba(17,16,14,.28); font-size: 13px; }
.theorem-punch span { padding: 7px 10px; background: var(--ink); color: white; border-radius: 3px; }.theorem-punch i { margin-left: 20px; font-family: var(--serif); font-size: 18px; }

.proof-section { background: var(--ink); color: white; }
.proof-section .section-heading > p { color: #aaa59c; }
.proof-lab { margin: 70px 0 0 95px; display: grid; grid-template-columns: 1.1fr .9fr; min-height: 600px; border: 1px solid rgba(255,255,255,.15); }
.proof-visual { position: relative; min-width: 0; background-image: linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px); background-size: 34px 34px; overflow: hidden; }
.zoom-scene { position: absolute; inset: 0; transition: .5s; }
.zoom-scene .needle-cloud { left: 49%; top: 48%; transform: translate(-50%,-50%) rotateX(59deg) rotateZ(-15deg) scale(.92); transition: .5s; }
.zoom-scene.zoom-1 .needle-cloud { transform: translate(-43%,-47%) rotateX(50deg) rotateZ(-5deg) scale(1.35); }
.zoom-scene.zoom-2 .needle-cloud { transform: translate(-58%,-52%) rotateX(66deg) rotateZ(-23deg) scale(1.8); }
.zoom-scene.zoom-3 .needle-cloud { transform: translate(-48%,-50%) rotateX(55deg) rotateZ(6deg) scale(2.15); }
.zoom-label { position: absolute; top: 22px; left: 24px; color: var(--cyan); font: italic 14px Georgia, serif; }
.focus-ring { position: absolute; left: 50%; top: 50%; width: 120px; height: 120px; transform: translate(-50%,-50%); border: 1px dashed var(--cyan); border-radius: 50%; transition: .45s; }
.zoom-1 .focus-ring { width: 240px; height: 240px; }.zoom-2 .focus-ring { width: 390px; height: 390px; opacity: .5; }.zoom-3 .focus-ring { width: 520px; height: 520px; opacity: .25; }
.convex-window { position: absolute; border: 1px solid var(--orange); background: rgba(255,92,53,.08); opacity: 0; transition: .4s; }
.zoom-2 .convex-window, .zoom-3 .convex-window { opacity: 1; }
.convex-window.one { width: 230px; height: 95px; left: 10%; top: 29%; transform: rotate(-22deg); }.convex-window.two { width: 270px; height: 110px; right: 5%; bottom: 23%; transform: rotate(18deg); border-color: var(--cyan); background: rgba(120,231,227,.06); }
.zoom-dots { position: absolute; left: 24px; bottom: 24px; display: flex; gap: 9px; }
.zoom-dots button { width: 30px; height: 30px; border: 1px solid rgba(255,255,255,.2); background: rgba(17,16,14,.75); color: #8d8981; cursor: pointer; }.zoom-dots button.active { background: var(--orange); color: white; border-color: var(--orange); }
.proof-copy { display: flex; flex-direction: column; justify-content: center; padding: 60px; border-left: 1px solid rgba(255,255,255,.15); }
.proof-copy h3 { margin: 0; font-family: var(--serif); font-size: 42px; line-height: 1.25; text-wrap: balance; }
.proof-copy p { min-height: 150px; color: #aaa59c; line-height: 1.9; }
.step-buttons { display: flex; gap: 10px; }
.step-buttons button { padding: 12px 18px; border: 1px solid rgba(255,255,255,.18); background: transparent; color: white; cursor: pointer; }
.step-buttons button.primary { background: white; color: var(--ink); }.step-buttons button:disabled { opacity: .25; cursor: not-allowed; }
.proof-honesty { margin: 20px 0 0 95px; padding: 25px 30px; display: grid; grid-template-columns: 150px 1fr; gap: 30px; border: 1px solid rgba(255,255,255,.12); color: #aaa59c; font-size: 12px; line-height: 1.7; }
.proof-honesty span { color: var(--orange-soft); font-weight: 800; }.proof-honesty p { margin: 0; }

.wave-section { min-height: 720px; padding-top: 0; padding-bottom: 0; display: grid; grid-template-columns: 1fr 1fr; background: var(--ink); color: white; }
.wave-field { position: relative; overflow: hidden; min-height: 720px; background: #151b1b; border-top: 1px solid rgba(255,255,255,.1); }
.wave-field::after { content: "WAVE PACKETS"; position: absolute; left: 25px; bottom: 22px; color: rgba(255,255,255,.25); font: 11px Georgia, serif; letter-spacing: .2em; }
.wave-field i { position: absolute; left: -30%; width: 160%; height: 2px; background: var(--cyan); opacity: .55; box-shadow: 0 0 14px var(--cyan); transform: rotate(-15deg); animation: waveTravel 4s ease-in-out infinite alternate; }
.wave-field i:nth-child(2n) { transform: rotate(18deg); background: var(--orange); box-shadow: 0 0 14px var(--orange); }
.wave-field i:nth-child(3n) { transform: rotate(3deg); }
@keyframes waveTravel { to { left: -10%; opacity: .15; } }
.wave-copy { padding: 90px max(28px, calc((100vw - 1120px)/2)) 90px 70px; display: flex; flex-direction: column; justify-content: center; border-top: 1px solid rgba(255,255,255,.1); }
.wave-copy h2 { margin: 0; font-family: var(--serif); font-size: clamp(42px, 4.4vw, 64px); line-height: 1.15; }
.wave-copy > p { color: #aaa59c; line-height: 1.9; }
.wave-chain { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin: 24px 0; padding: 20px 0; border-top: 1px solid rgba(255,255,255,.14); border-bottom: 1px solid rgba(255,255,255,.14); font-size: 12px; }
.wave-chain span { padding: 7px 9px; background: rgba(255,255,255,.08); }.wave-chain b { color: var(--orange); }
.important-note { padding-left: 18px; border-left: 2px solid var(--orange); font-size: 13px; }.important-note b { color: white; }

.impact-grid { margin: 65px 0 0 95px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.impact-card { min-height: 390px; padding: 28px; display: flex; flex-direction: column; border: 1px solid var(--line); background: #faf8f3; }
.impact-card.level-3 { background: var(--ink); color: white; }.impact-card.level-2 { background: #dedad0; }
.impact-top { display: flex; justify-content: space-between; align-items: center; font-size: 10px; font-weight: 800; letter-spacing: .12em; }
.impact-top > div { display: flex; gap: 4px; }.impact-top i { width: 7px; height: 7px; border-radius: 50%; border: 1px solid #aaa; }.impact-top i.on { background: var(--orange); border-color: var(--orange); }
.impact-card h3 { margin: 60px 0 18px; font-family: var(--serif); font-size: 29px; line-height: 1.25; text-wrap: balance; }
.impact-card p { color: var(--muted); font-size: 14px; line-height: 1.8; }.impact-card.level-3 p { color: #aaa59c; }
.impact-card small { margin-top: auto; padding-top: 22px; border-top: 1px solid var(--line); color: var(--orange); line-height: 1.6; }.impact-card.level-3 small { border-color: rgba(255,255,255,.15); }
.impact-verdict { margin: 22px 0 0 95px; padding: 55px; display: grid; grid-template-columns: 160px 1fr; align-items: center; background: var(--orange); }
.verdict-mark { font: 140px Georgia, serif; line-height: .8; }
.impact-verdict .eyebrow { color: var(--ink); }.impact-verdict h3 { margin: 0; font-family: var(--serif); font-size: 34px; }.impact-verdict p { max-width: 750px; line-height: 1.8; }

.recap-section { background: #dedad0; }
.recap-section > .eyebrow { margin-left: 95px; }
.recap-section ol { list-style: none; counter-reset: recap; margin: 40px 0 0 95px; padding: 0; border-top: 1px solid var(--line); }
.recap-section li { counter-increment: recap; display: grid; grid-template-columns: 180px 1fr; gap: 30px; padding: 27px 0; border-bottom: 1px solid var(--line); align-items: center; }
.recap-section li b { font-family: var(--serif); font-size: 28px; }.recap-section li b::before { content: "0" counter(recap) " / "; color: var(--orange); font: italic 12px Georgia, serif; }.recap-section li span { color: var(--muted); }
.sources-section { padding: 100px max(28px, calc((100vw - 1120px)/2)); display: grid; grid-template-columns: .8fr 1.2fr; gap: 90px; background: var(--paper); }
.sources-section h2 { font-size: 45px; }
.source-list { border-top: 1px solid var(--line); }
.source-list a { display: grid; grid-template-columns: 1fr 1fr 30px; gap: 20px; align-items: center; padding: 24px 0; border-bottom: 1px solid var(--line); transition: color .2s; }.source-list a:hover { color: var(--orange); }.source-list b { font-size: 14px; }.source-list span { color: var(--muted); font-size: 12px; }.source-list i { font-style: normal; }
footer { padding: 42px max(28px, calc((100vw - 1120px)/2)); display: flex; justify-content: space-between; align-items: center; background: var(--ink); color: #77736c; font-size: 11px; } footer .brand { color: white; } footer a:hover { color: white; }

@media (max-width: 900px) {
  .nav-shell { top: 12px; }.menu-button { display: block; }.nav-links { position: absolute; top: 70px; left: 0; right: 0; padding: 8px; display: none; flex-direction: column; align-items: stretch; background: rgba(17,16,14,.96); border-radius: 5px; }.nav-links.open { display: flex; }
  .hero { grid-template-columns: 1fr; padding-top: 140px; min-height: auto; }.hero-art { height: 500px; margin-top: 20px; }.hero-footnote { display: none; }
  .chapter-number { display: none; }.section-heading, .definition-card, .correction, .measure-toggle, .zero-vs-three, .scale-lab, .proof-lab, .proof-honesty, .impact-grid, .impact-verdict, .recap-section > .eyebrow, .recap-section ol { margin-left: 0; }
  .plane-story, .wave-section, .sources-section { grid-template-columns: 1fr; }.wave-copy { padding: 80px 28px; }.wave-field { min-height: 430px; }.definition-card { grid-template-columns: 1fr; }.formula { border-right: 0; border-bottom: 1px solid var(--line); }.proof-lab { grid-template-columns: 1fr; }.proof-visual { min-height: 500px; }.proof-copy { border-left: 0; border-top: 1px solid rgba(255,255,255,.15); }.impact-grid { grid-template-columns: 1fr; }.impact-card { min-height: 320px; }.impact-verdict { grid-template-columns: 120px 1fr; }.sources-section { gap: 45px; }
}

@media (max-width: 600px) {
  .hero { padding-left: 20px; padding-right: 20px; }.hero h1 { font-size: 59px; }.hero-lead { font-size: 15px; }.hero-actions { align-items: flex-start; flex-direction: column; }.hero-art { height: 390px; transform: scale(.83); transform-origin: center; }.needle-cloud { width: 360px; height: 360px; }.needle-cloud i { width: 270px; }
  .chapter { padding: 90px 20px; }.section-heading h2 { font-size: 42px; }.section-heading > p { font-size: 15px; }.definition-card { margin-top: 45px; }.formula { padding: 30px 24px; font-size: 25px; }.formula-translation { padding: 30px 24px; }.correction { padding: 26px 22px; }.correction-grid { grid-template-columns: 1fr; gap: 22px; }.correction-grid > div + div { border-left: 0; border-top: 1px solid rgba(17,16,14,.18); padding: 22px 0 0; }.plane-story { gap: 45px; margin-top: 80px; }.plane-visual { min-height: 330px; }
  .zero-vs-three { grid-template-columns: 100px 1fr; padding: 30px 20px; }.zero-symbol { font-size: 120px; }.zero-vs-three h3 { font-size: 25px; }.scale-lab { padding: 25px 20px; }.lab-controls { flex-direction: column; align-items: stretch; }.lab-controls label { min-width: 0; }.dimension-stage { grid-template-columns: 1fr; padding: 30px 0; }.cube-wrap { width: 200px; height: 200px; }.theorem-card { padding: 48px 24px; }.theorem-punch { flex-wrap: wrap; }.proof-lab { min-height: 0; }.proof-visual { min-height: 390px; }.proof-copy { padding: 36px 24px; }.proof-copy h3 { font-size: 33px; }.proof-copy p { min-height: 0; }.proof-honesty { grid-template-columns: 1fr; gap: 8px; }.wave-field { min-height: 340px; }.wave-copy h2 { font-size: 40px; }.impact-grid { margin-top: 45px; }.impact-verdict { padding: 35px 24px; grid-template-columns: 1fr; }.verdict-mark { font-size: 90px; }.recap-section li { grid-template-columns: 1fr; gap: 8px; }.source-list a { grid-template-columns: 1fr 24px; }.source-list span { grid-column: 1; grid-row: 2; }.source-list i { grid-column: 2; grid-row: 1 / span 2; } footer { flex-direction: column; gap: 22px; text-align: center; }
  .formula { gap: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation: none !important; transition-duration: .01ms !important; }
}