:root {
  --optical-white: #f4f6f9;
  --surface: #fbfcfd;
  --graphite: #13161b;
  --muted: #69717d;
  --platinum: #a8b0bc;
  --line: #d7dce4;
  --cobalt: #2f5bff;
  --ice: #e9efff;
  --film-shell: min(2160px, calc(100vw - 8rem));
  --sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", Arial, sans-serif;
  --serif: "Songti SC", "STSong", "SimSun", serif;
  --mono: "SFMono-Regular", "SF Mono", Menlo, Consolas, monospace;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-snap-type: y mandatory; background: var(--optical-white); }
body { margin: 0; overflow-x: hidden; color: var(--graphite); background: var(--optical-white); font-family: var(--sans); -webkit-font-smoothing: antialiased; }
body.is-directory-open { overflow: hidden; }
a { color: inherit; text-decoration: none; }
button { color: inherit; font: inherit; }
h1, h2, h3, p, blockquote { margin-top: 0; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--cobalt); outline-offset: 5px; }
.skip-link { position: fixed; top: 1rem; left: 1rem; z-index: 100; padding: .7rem 1rem; color: white; background: var(--graphite); transform: translateY(-180%); transition: transform 180ms ease; }
.skip-link:focus { transform: translateY(0); }

.film-header { position: fixed; top: 0; left: 0; right: 0; z-index: 30; min-height: 5.5rem; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; width: var(--film-shell); margin-inline: auto; pointer-events: none; }
.film-header::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 1px; background: rgba(19, 22, 27, .12); transform: scaleX(0); transform-origin: left; transition: transform 500ms ease; }
.film-header.is-scrolled::after { transform: scaleX(1); }
.film-brand, .directory-toggle, .film-header__state { pointer-events: auto; }
.film-brand { display: flex; align-items: baseline; gap: .55rem; width: fit-content; white-space: nowrap; }
.film-brand__primary { font-size: 1.03rem; font-weight: 720; }
.film-brand__cn { font-family: var(--serif); font-size: 1.05rem; font-weight: 600; }
.film-brand i { width: 1px; height: .9rem; margin-inline: .1rem; background: var(--platinum); }
.film-brand__lab { color: var(--muted); font-size: .68rem; }
.film-header__state { display: flex; align-items: center; gap: .65rem; color: var(--muted); font: .62rem var(--mono); }
.film-header__state i { width: 3.6rem; height: 1px; overflow: hidden; background: var(--line); }
.film-header__state i::after { content: ""; display: block; width: var(--chapter-progress, 14.285%); height: 100%; background: var(--graphite); transition: width 500ms ease; }
.directory-toggle { justify-self: end; display: flex; align-items: center; gap: .85rem; padding: .75rem 0 .75rem 1rem; border: 0; background: transparent; cursor: pointer; font-size: .72rem; }
.directory-toggle i { position: relative; width: 1.25rem; height: .7rem; }
.directory-toggle i::before, .directory-toggle i::after { content: ""; position: absolute; right: 0; width: 100%; height: 1px; background: currentColor; }
.directory-toggle i::before { top: .12rem; }
.directory-toggle i::after { bottom: .12rem; width: 66%; }

.chapter-rail { position: fixed; top: 50%; right: max(1.5rem, calc((100vw - min(2160px, calc(100vw - 8rem))) / 2)); z-index: 25; display: grid; gap: .32rem; transform: translateY(-50%); }
.chapter-rail a { display: flex; align-items: center; justify-content: flex-end; gap: .7rem; min-width: 2.75rem; min-height: 1.65rem; color: var(--platinum); font: .58rem var(--mono); }
.chapter-rail a i { width: .9rem; height: 1px; background: currentColor; transition: width 240ms ease, background 240ms ease; }
.chapter-rail a span { opacity: 0; transform: translateX(.4rem); transition: opacity 200ms ease, transform 200ms ease; }
.chapter-rail a:hover span, .chapter-rail a:focus-visible span, .chapter-rail a[aria-current="step"] span { opacity: 1; transform: none; }
.chapter-rail a[aria-current="step"] { color: var(--graphite); }
.chapter-rail a[aria-current="step"] i { width: 1.8rem; background: var(--cobalt); }

.chapter-directory { position: fixed; inset: 0; z-index: 50; padding: 2.25rem max(3rem, calc((100vw - min(1280px, calc(100vw - 6rem))) / 2)); color: var(--surface); background: rgba(19, 22, 27, .98); overflow: auto; overscroll-behavior: contain; }
.chapter-directory[hidden] { display: none; }
.chapter-directory__top { display: flex; justify-content: space-between; align-items: center; padding-bottom: 1.5rem; border-bottom: 1px solid rgba(255, 255, 255, .16); }
.chapter-directory__top p { margin: 0; color: var(--platinum); font: .68rem var(--mono); }
.directory-close { position: relative; width: 2.75rem; height: 2.75rem; border: 0; background: transparent; cursor: pointer; }
.directory-close i::before, .directory-close i::after { content: ""; position: absolute; top: 50%; left: .65rem; width: 1.45rem; height: 1px; background: white; transform: rotate(45deg); }
.directory-close i::after { transform: rotate(-45deg); }
.chapter-directory nav { display: grid; padding-block: 4rem; }
.chapter-directory nav a { display: grid; grid-template-columns: 4rem 1fr; align-items: baseline; padding: 1rem 0; border-bottom: 1px solid rgba(255, 255, 255, .1); }
.chapter-directory nav span { color: #777f8a; font: .66rem var(--mono); }
.chapter-directory nav strong { font-size: 2.25rem; font-weight: 520; }
.chapter-directory nav a:hover strong, .chapter-directory nav a:focus-visible strong { color: #8ca6ff; }

.chapter { position: relative; min-height: 100dvh; overflow: hidden; scroll-snap-align: start; scroll-snap-stop: always; isolation: isolate; }
.chapter::before { content: ""; position: absolute; inset: 0; z-index: -2; background: var(--optical-white); }
.chapter__frame { width: var(--film-shell); min-height: 100dvh; margin-inline: auto; padding: 8rem 3rem 5rem 0; display: grid; align-items: center; }
.chapter__center { min-height: 100dvh; width: min(86rem, calc(100vw - 8rem)); margin-inline: auto; padding: 8rem 0 6rem; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; }
.chapter__kicker, .chapter__index { color: var(--muted); font: .66rem var(--mono); }
.chapter h1, .chapter h2 { margin-bottom: 0; font-size: 5.25rem; line-height: 1.06; letter-spacing: 0; }
.chapter h1 { font-weight: 680; }
.chapter h2 { font-weight: 640; }
.chapter h2 em { color: var(--cobalt); font-style: normal; font-weight: inherit; }
.title-line { display: block; white-space: nowrap; }
.chapter__narration { margin: 2.1rem 0 0; color: #333941; font-family: var(--serif); font-size: 1.35rem; line-height: 1.85; }
.chapter__narration--left { max-width: 42rem; text-align: left; }
.chapter__fact { max-width: 58rem; margin: 2.4rem 0 0; color: var(--muted); font-size: .9rem; line-height: 1.9; text-wrap: balance; }
.chapter__fact--left { max-width: 39rem; margin-top: 1.5rem; text-align: left; }
.neural-field { position: absolute; inset: 0; z-index: -1; width: 100%; height: 100%; pointer-events: none; }
.neural-field--opening { opacity: .5; }
.neural-field--philosophy { opacity: .34; }

.chapter--opening { background: var(--optical-white); }
.chapter__center--opening { width: min(96rem, calc(100vw - 8rem)); padding-bottom: 9rem; }
.chapter--opening h1 { max-width: none; margin-top: 1.35rem; font-size: 6rem; }
.chapter--opening .chapter__fact { margin-top: 3.1rem; }
.opening-signal { position: absolute; left: 50%; bottom: 10.5%; display: flex; align-items: center; gap: .8rem; color: var(--muted); font: .58rem var(--mono); transform: translateX(-50%); }
.opening-signal i { width: 4.5rem; height: 1px; background: var(--line); }
.opening-signal b { width: .38rem; height: .38rem; background: var(--cobalt); box-shadow: 0 0 0 .45rem var(--ice); }
.chapter-next { position: absolute; left: max(3rem, calc((100vw - min(2160px, calc(100vw - 8rem))) / 2)); bottom: 2.5rem; display: flex; align-items: center; gap: 1rem; color: var(--muted); font-size: .68rem; }
.chapter-next i { width: 1px; height: 2rem; background: var(--cobalt); transform-origin: top; animation: next-pulse 2.4s ease-in-out infinite; }

.chapter--practice::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 28%; z-index: -1; background: #eef1f5; border-top: 1px solid rgba(168, 176, 188, .18); }
.practice-backdrop { position: absolute; top: 13%; right: max(5rem, calc((100vw - var(--film-shell)) / 2 + 3rem)); bottom: 20%; z-index: -1; width: min(45vw, 70rem); color: rgba(105, 113, 125, .42); border-block: 1px solid rgba(168, 176, 188, .2); }
.practice-backdrop::before, .practice-backdrop::after { content: ""; position: absolute; background: rgba(168, 176, 188, .22); }
.practice-backdrop::before { top: 0; bottom: 0; left: 34%; width: 1px; }
.practice-backdrop::after { top: 61%; left: 0; right: 0; height: 1px; }
.practice-backdrop span { position: absolute; top: 1.1rem; font: .5rem var(--mono); }
.practice-backdrop span:nth-of-type(1) { left: 0; }
.practice-backdrop span:nth-of-type(2) { left: 39%; }
.practice-backdrop span:nth-of-type(3) { right: 0; }
.practice-backdrop i { position: absolute; top: 1.35rem; height: 1px; background: rgba(47, 91, 255, .25); }
.practice-backdrop i:nth-of-type(1) { left: 11%; width: 20%; }
.practice-backdrop i:nth-of-type(2) { right: 15%; width: 20%; }
.practice-backdrop b { position: absolute; width: .32rem; height: .32rem; background: rgba(47, 91, 255, .42); box-shadow: 0 0 0 .35rem rgba(233, 239, 255, .55); }
.practice-backdrop b:nth-of-type(1) { top: 29%; left: 34%; }
.practice-backdrop b:nth-of-type(2) { top: 61%; left: 14%; }
.practice-backdrop b:nth-of-type(3) { top: 61%; left: 68%; }
.practice-backdrop b:nth-of-type(4) { right: 5%; bottom: 7%; }
.chapter--practice .chapter__frame { grid-template-columns: minmax(0, 1.18fr) minmax(26rem, .82fr); gap: 6rem; }
.chapter__copy--wide h2 { max-width: none; font-size: 4.25rem; }
.chapter__copy .chapter__index { margin-bottom: 1.6rem; }
.practice-visual { align-self: center; display: grid; gap: 2.7rem; min-width: 0; }
.practice-code { position: relative; min-height: 22rem; padding: 1.2rem 1.35rem 1rem; overflow: hidden; background: rgba(255, 255, 255, .92); border: 1px solid var(--line); box-shadow: 1rem 1rem 0 rgba(215, 220, 228, .3), 0 1.5rem 4rem rgba(67, 77, 92, .06); }
.practice-code::before { content: ""; position: absolute; inset: .45rem; pointer-events: none; border: 1px solid rgba(215, 220, 228, .38); }
.practice-code__top, .practice-code__meta { display: flex; align-items: center; justify-content: space-between; color: var(--muted); font: .55rem var(--mono); }
.practice-code__top { padding-bottom: .9rem; border-bottom: 1px solid var(--line); }
.practice-code__top span:last-child { color: var(--cobalt); }
.practice-code__top i { display: inline-block; width: .35rem; height: .35rem; margin-right: .35rem; background: var(--cobalt); }
.practice-code__meta { padding: 1rem 0 .8rem; color: var(--platinum); }
.practice-code__viewport { position: relative; height: 13.6rem; overflow: hidden; border-top: 1px solid var(--line); }
.practice-code__viewport::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 2.2rem; pointer-events: none; background: rgba(255, 255, 255, .72); }
.practice-code__lines { will-change: transform; animation: code-drift 22s linear infinite; }
.practice-code__loop { padding: .65rem 0 1.35rem; }
.practice-code__lines p { display: grid; grid-template-columns: 2rem 1fr; gap: .65rem; margin: 0; color: #505966; font: .68rem/2 var(--mono); white-space: nowrap; }
.practice-code__lines b { color: var(--platinum); font-weight: 400; text-align: right; }
.practice-code__lines em { color: var(--cobalt); font-style: normal; }
.practice-code__lines strong { color: var(--graphite); font-weight: 600; }
.practice-code__cursor { position: absolute; right: 1.35rem; bottom: 1.25rem; width: .38rem; height: .75rem; background: var(--cobalt); animation: cursor-blink 1.1s steps(2, jump-none) infinite; }
.practice-spectrum { align-self: end; display: grid; margin-bottom: 3rem; border-top: 1px solid var(--platinum); }
.practice-spectrum article { display: grid; grid-template-columns: 2.6rem 5rem 1fr; align-items: baseline; padding: 1.35rem 0; border-bottom: 1px solid var(--line); }
.practice-spectrum span { color: var(--cobalt); font: .62rem var(--mono); }
.practice-spectrum h3 { margin: 0; font-size: 1.15rem; }
.practice-spectrum p { margin: 0; color: var(--muted); font-size: .78rem; line-height: 1.7; }

.chapter--philosophy::after { content: ""; position: absolute; left: 50%; bottom: 0; width: min(64rem, 72vw); height: .65rem; background: var(--graphite); transform: translateX(-50%); }
.chapter__center--philosophy { width: min(96rem, calc(100vw - 9rem)); }
.chapter--philosophy h2 { max-width: none; margin-top: 1.7rem; }
.chapter--philosophy blockquote { max-width: 50rem; margin: 3.2rem 0 0; color: #343a42; font-family: var(--serif); font-size: 1.22rem; line-height: 2; }
.philosophy-axis { position: absolute; left: 50%; top: 15%; display: flex; align-items: center; gap: .8rem; color: #9da4ae; font: .52rem var(--mono); transform: translateX(-50%); }
.philosophy-axis i { width: 2.75rem; height: 1px; background: var(--line); }

.chapter--intelligence::before { background: #f1f6fb; }
.chapter__frame--product { grid-template-columns: minmax(25rem, .72fr) minmax(38rem, 1.28fr); gap: 7rem; }
.product-intro h2 { max-width: 36rem; margin-bottom: 1.7rem; }
.product-claim { max-width: 39rem; margin: 0; color: #303943; font-family: var(--serif); font-size: 1.1rem; line-height: 1.85; }
.capability-line { display: flex; flex-wrap: wrap; gap: .55rem 1.2rem; margin: 2rem 0 0; padding: 1.35rem 0 0; border-top: 1px solid var(--line); list-style: none; color: #526171; font-size: .7rem; }
.capability-line li::before { content: "+"; margin-right: .35rem; color: var(--cobalt); }
.product-link, .contact-link { display: inline-flex; align-items: center; gap: 1.4rem; margin-top: 2.2rem; padding-bottom: .45rem; border-bottom: 1px solid currentColor; font-size: .78rem; font-weight: 650; }
.product-link span, .contact-link span { color: var(--cobalt); font-size: 1rem; }
.intelligence-console { position: relative; min-height: 35rem; padding: 1.7rem; color: #e8edf5; background: #17212e; box-shadow: 0 2rem 5rem rgba(34, 59, 86, .13); }
.console-top, .console-heading, .console-flow > div { display: flex; justify-content: space-between; align-items: center; }
.console-top { padding-bottom: 1.2rem; color: #8f9cac; border-bottom: 1px solid #334151; font: .57rem var(--mono); }
.console-top span:last-child { color: #8fb3ff; }
.console-top i { display: inline-block; width: .38rem; height: .38rem; margin-right: .35rem; background: #5b87ff; }
.console-heading { align-items: end; margin: 3rem 0 2rem; }
.console-heading p { margin: 0; color: #8997a7; font: .62rem var(--mono); }
.console-heading strong { font-size: 1.55rem; font-weight: 560; }
.console-metrics { display: grid; grid-template-columns: repeat(3, 1fr); border-block: 1px solid #334151; }
.console-metrics div { min-height: 9rem; padding: 1.35rem; border-right: 1px solid #334151; }
.console-metrics div:last-child { border-right: 0; }
.console-metrics small, .console-metrics span { display: block; color: #8896a7; font-size: .63rem; }
.console-metrics b { display: block; margin: 1rem 0 .6rem; color: #8fb3ff; font-size: 2.6rem; font-weight: 520; }
.console-flow { margin-top: 1.6rem; }
.console-flow > div { justify-content: initial; gap: 1rem; padding: 1rem 0; border-bottom: 1px solid #2d3b4a; }
.console-flow > div > i { width: .42rem; height: .42rem; flex: 0 0 auto; background: #6b91f4; }
.console-flow span { flex: 1; }
.console-flow b, .console-flow small { display: block; }
.console-flow b { font-size: .73rem; font-weight: 540; }
.console-flow small { margin-top: .25rem; color: #7e8b9b; font: .55rem var(--mono); }
.console-flow em { color: #8f9cac; font: normal .52rem var(--mono); }
.console-disclaimer { position: absolute; left: 1.7rem; bottom: 1.2rem; margin: 0; color: #788697; font-size: .55rem; }

.chapter--weden, .chapter--weden::before { background: var(--optical-white); }
.chapter__frame--weden { grid-template-columns: minmax(35rem, 1.15fr) minmax(28rem, .85fr); gap: 8rem; }
.weden-structure { position: relative; min-height: min(68dvh, 46rem); overflow: hidden; border-block: 1px solid var(--line); }
.neural-field--weden { z-index: 0; opacity: .9; }
.weden-structure::before, .weden-structure::after { content: ""; position: absolute; z-index: 1; background: var(--line); }
.weden-structure::before { top: 50%; left: 0; right: 0; height: 1px; }
.weden-structure::after { top: 0; bottom: 0; left: 50%; width: 1px; }
.weden-core { position: absolute; top: 50%; left: 50%; z-index: 3; width: 12rem; height: 12rem; display: flex; flex-direction: column; align-items: center; justify-content: center; color: var(--graphite); background: rgba(244, 246, 249, .92); border: 1px solid var(--graphite); transform: translate(-50%, -50%); }
.weden-core::before { content: ""; position: absolute; inset: .5rem; border: 1px solid var(--line); }
.weden-core span { font-size: .72rem; font-weight: 760; }
.weden-core strong { margin-top: .25rem; font-family: var(--serif); font-size: 1.7rem; font-weight: 600; }
.weden-core small { max-width: 8rem; margin-top: .7rem; color: var(--muted); font-size: .52rem; line-height: 1.6; text-align: center; }
.weden-node { position: absolute; z-index: 2; display: flex; align-items: center; gap: .7rem; padding: .55rem .75rem; color: #4f5761; background: rgba(244, 246, 249, .86); border: 1px solid var(--line); font-size: .68rem; }
.weden-node i { color: var(--cobalt); font: normal .52rem var(--mono); }
.weden-node--idea { top: 14%; left: 9%; }
.weden-node--visual { top: 17%; right: 8%; }
.weden-node--client { bottom: 14%; left: 13%; }
.weden-node--project { right: 12%; bottom: 16%; }
.weden-copy { align-self: center; max-width: 50rem; padding-right: 0; }
.weden-wordmark { margin: 0 0 2.3rem; color: var(--graphite); font-size: 1rem; font-weight: 720; }
.weden-wordmark span { margin-left: .4rem; font-family: var(--serif); font-weight: 600; }
.weden-copy h2 { margin-bottom: 2rem; color: var(--graphite); }
.chapter--weden .chapter__fact { color: var(--muted); }
.product-link--weden span { color: var(--cobalt); }

.chapter--method::before { background: #f8f9fb; }
.chapter__center--method { width: min(94rem, calc(100vw - 8rem)); }
.chapter--method h2 { margin-top: 1.7rem; }
.method-sequence { width: 100%; display: grid; grid-template-columns: repeat(4, 1fr); margin: 4.5rem 0 0; padding: 0; border-top: 1px solid var(--platinum); list-style: none; text-align: left; }
.method-sequence li { position: relative; min-height: 9rem; padding: 1.5rem 1.4rem 0 0; border-right: 1px solid var(--line); }
.method-sequence li:last-child { border-right: 0; padding-left: 1.4rem; }
.method-sequence li:not(:first-child) { padding-left: 1.4rem; }
.method-sequence span { color: var(--cobalt); font: .6rem var(--mono); }
.method-sequence strong { display: block; margin-top: 1.35rem; font-size: 1.2rem; }
.method-sequence p { margin: .35rem 0 0; color: var(--muted); font-size: .72rem; }

.chapter--contact::before { background: white; }
.chapter__center--contact { position: relative; z-index: 2; }
.chapter--contact h2 { margin-top: 1.7rem; }
.contact-link { margin-top: 2.8rem; font-size: 1rem; }
.contact-signal { position: absolute; inset: 15% 10%; }
.contact-signal i { position: absolute; background: #e9ecf1; }
.contact-signal i:nth-child(1), .contact-signal i:nth-child(2) { top: 50%; width: 30%; height: 1px; }
.contact-signal i:nth-child(1) { left: 0; }
.contact-signal i:nth-child(2) { right: 0; }
.contact-signal i:nth-child(3), .contact-signal i:nth-child(4) { left: 50%; width: 1px; height: 22%; }
.contact-signal i:nth-child(3) { top: 0; }
.contact-signal i:nth-child(4) { bottom: 0; }
.film-footer { position: absolute; left: 0; right: 0; bottom: 0; width: var(--film-shell); min-height: 4.8rem; margin-inline: auto; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; color: #858d98; border-top: 1px solid var(--line); font-size: .6rem; }
.film-footer span:nth-child(2) { text-align: center; }
.film-footer span:last-child { text-align: right; }

.chapter__center > *, .chapter__copy > *, .practice-visual, .practice-code, .practice-spectrum, .intelligence-console, .weden-copy > *, .weden-structure, .method-sequence {
  opacity: 0;
  transform: translateY(1.5rem);
  transition: opacity 700ms cubic-bezier(.2,.75,.2,1), transform 700ms cubic-bezier(.2,.75,.2,1);
}
.chapter.is-active .chapter__center > *, .chapter.is-active .chapter__copy > *, .chapter.is-active .practice-visual, .chapter.is-active .practice-code, .chapter.is-active .practice-spectrum, .chapter.is-active .intelligence-console, .chapter.is-active .weden-copy > *, .chapter.is-active .weden-structure, .chapter.is-active .method-sequence { opacity: 1; transform: none; }
.chapter.is-active .chapter__center > *:nth-child(2), .chapter.is-active .chapter__copy > *:nth-child(2), .chapter.is-active .weden-copy > *:nth-child(2) { transition-delay: 90ms; }
.chapter.is-active .chapter__center > *:nth-child(3), .chapter.is-active .chapter__copy > *:nth-child(3), .chapter.is-active .weden-copy > *:nth-child(3) { transition-delay: 170ms; }
.chapter.is-active .chapter__center > *:nth-child(n+4), .chapter.is-active .chapter__copy > *:nth-child(n+4), .chapter.is-active .weden-copy > *:nth-child(n+4), .chapter.is-active .practice-spectrum, .chapter.is-active .intelligence-console, .chapter.is-active .method-sequence { transition-delay: 250ms; }

@keyframes next-pulse { 0%, 100% { transform: scaleY(.35); opacity: .45; } 50% { transform: scaleY(1); opacity: 1; } }
@keyframes code-drift { to { transform: translateY(-50%); } }
@keyframes cursor-blink { 0%, 45% { opacity: 1; } 46%, 100% { opacity: .18; } }

@media (min-width: 2300px) {
  :root { --film-shell: min(2400px, calc(100vw - 10rem)); }
  .chapter h1, .chapter h2 { font-size: 5.8rem; }
  .chapter--opening h1 { font-size: 6.5rem; }
  .chapter__copy--wide h2 { font-size: 5.25rem; }
  .chapter__frame--weden { gap: 10rem; }
}

@media (min-width: 3200px) {
  :root { --film-shell: min(2800px, calc(100vw - 14rem)); }
  .chapter h1, .chapter h2 { font-size: 6.8rem; }
  .chapter--opening h1 { font-size: 8rem; }
  .chapter__copy--wide h2 { font-size: 6rem; }
  .chapter__center--opening, .chapter__center--philosophy { width: min(120rem, calc(100vw - 12rem)); }
}

@media (max-width: 1600px) and (min-width: 821px) {
  .chapter h1, .chapter h2 { font-size: 4.5rem; }
  .chapter--opening h1 { font-size: 5.2rem; }
  .chapter__copy--wide h2 { font-size: 3.25rem; }
  .chapter__center--opening { width: min(83rem, calc(100vw - 6rem)); }
  .chapter--practice .chapter__frame { gap: 4.5rem; grid-template-columns: minmax(0, 1.18fr) minmax(25rem, .82fr); }
  .chapter__frame--product { gap: 4rem; grid-template-columns: minmax(22rem, .8fr) minmax(34rem, 1.2fr); }
}

@media (max-width: 1180px) and (min-width: 821px) {
  :root { --film-shell: calc(100vw - 4rem); }
  .film-header { min-height: 4.8rem; }
  .chapter__frame { padding: 7rem 2rem 4rem 0; }
  .chapter h1, .chapter h2 { font-size: 4rem; }
  .chapter--opening h1 { font-size: 4.6rem; }
  .chapter__copy--wide h2 { font-size: 3.1rem; }
  .chapter--practice .title-line { white-space: normal; overflow-wrap: anywhere; }
  .chapter--practice .chapter__frame { gap: 2.5rem; grid-template-columns: minmax(0, 1.22fr) minmax(22rem, .78fr); }
  .chapter__frame--product { gap: 2.5rem; grid-template-columns: minmax(20rem, .8fr) minmax(28rem, 1.2fr); }
  .chapter-rail { right: 1.2rem; }
}

@media (max-height: 820px) and (min-width: 821px) {
  .film-header { min-height: 4.5rem; }
  .chapter__frame, .chapter__center { padding-top: 6.5rem; padding-bottom: 4rem; }
  .chapter--opening h1 { font-size: 4.7rem; }
  .chapter h1, .chapter h2 { font-size: 4.2rem; }
  .chapter__copy--wide h2 { font-size: 3.1rem; }
  .chapter__narration { margin-top: 1.4rem; }
  .chapter__fact { margin-top: 1.4rem; }
}

@media (max-width: 820px) {
  :root { --film-shell: calc(100vw - 2.5rem); }
  html { scroll-snap-type: y proximity; }
  .film-header { min-height: 4.5rem; grid-template-columns: 1fr auto; background: rgba(244, 246, 249, .86); border-bottom: 1px solid rgba(19, 22, 27, .1); backdrop-filter: blur(16px); }
  .film-brand__lab, .film-header__state, .chapter-rail { display: none; }
  .film-brand i { display: none; }
  .chapter { min-height: 100dvh; }
  .chapter__center { width: calc(100vw - 3rem); padding: 7rem 0 5rem; }
  .chapter__frame { width: calc(100vw - 3rem); min-height: 100dvh; padding: 7rem 0 4.5rem; grid-template-columns: 1fr !important; gap: 3.2rem; }
  .title-line { white-space: normal; }
  .chapter h1, .chapter h2, .chapter--opening h1, .chapter__copy--wide h2 { font-size: 3rem; line-height: 1.12; }
  .chapter__center--opening { padding-bottom: 8rem; }
  .chapter__narration { font-size: 1rem; }
  .chapter__fact { font-size: .78rem; line-height: 1.8; }
  .chapter-next { left: 1.5rem; bottom: 1.5rem; }
  .opening-signal { bottom: 8.5rem; }
  .chapter--practice::after { height: 36%; }
  .practice-backdrop { top: 49%; right: 0; bottom: 12%; width: 88%; opacity: .62; }
  .practice-spectrum { align-self: auto; margin-bottom: 0; }
  .practice-visual { gap: 2rem; }
  .practice-code { min-height: 19rem; padding-inline: .9rem; }
  .practice-code__viewport { height: 11rem; }
  .practice-code__lines p { font-size: .58rem; grid-template-columns: 1.7rem 1fr; gap: .4rem; }
  .practice-code__cursor { right: .9rem; }
  .practice-spectrum article { grid-template-columns: 2.2rem 4rem 1fr; }
  .philosophy-axis { display: none; }
  .chapter--philosophy blockquote { margin-top: 2.2rem; font-size: 1rem; }
  .chapter__center--philosophy { width: calc(100vw - 3rem); }
  .intelligence-console { min-height: 30rem; padding: 1.1rem; }
  .console-heading { margin: 2rem 0 1.5rem; }
  .console-heading strong { font-size: 1.15rem; }
  .console-metrics div { min-height: 7rem; padding: .85rem; }
  .console-metrics b { font-size: 1.8rem; }
  .console-metrics span { display: none; }
  .console-disclaimer { left: 1.1rem; }
  .chapter--weden { min-height: auto; }
  .chapter__frame--weden { min-height: auto; padding-bottom: 7rem; }
  .weden-structure { min-height: 56dvh; }
  .weden-copy { max-width: none; padding: 4rem 0 0; }
  .weden-core { width: 9rem; height: 9rem; }
  .weden-core small { max-width: 6.5rem; }
  .method-sequence { grid-template-columns: 1fr 1fr; margin-top: 3rem; }
  .method-sequence li:nth-child(2) { border-right: 0; }
  .method-sequence li:nth-child(n+3) { border-top: 1px solid var(--line); }
  .film-footer { width: calc(100vw - 3rem); grid-template-columns: 1fr auto; }
  .film-footer span:nth-child(2) { display: none; }
  .chapter-directory { padding: 1.5rem; }
  .chapter-directory nav { padding-block: 2rem; }
  .chapter-directory nav a { grid-template-columns: 2.5rem 1fr; }
  .chapter-directory nav strong { font-size: 1.35rem; }
}

@media (max-width: 460px) {
  .film-brand { gap: .3rem; }
  .film-brand__primary, .film-brand__cn { font-size: .9rem; }
  .chapter h1, .chapter h2, .chapter--opening h1, .chapter__copy--wide h2 { font-size: 2.55rem; }
  .chapter__center, .chapter__frame { width: calc(100vw - 2rem); }
  .opening-signal i { width: 2rem; }
  .practice-spectrum article { grid-template-columns: 1.8rem 3.5rem 1fr; }
  .console-flow em { display: none; }
  .console-flow b { font-size: .66rem; }
  .method-sequence p { font-size: .64rem; }
  .film-footer { width: calc(100vw - 2rem); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; scroll-snap-type: none; }
  *, *::before, *::after { animation: none !important; transition-duration: .01ms !important; }
  .chapter__center > *, .chapter__copy > *, .practice-visual, .practice-code, .practice-spectrum, .intelligence-console, .weden-copy > *, .weden-structure, .method-sequence { opacity: 1; transform: none; }
}

@media (prefers-reduced-transparency: reduce) {
  .chapter-directory { background: var(--graphite); }
}