:root {
  --paper: #f3f0e9;
  --paper-light: #faf8f3;
  --ink: #20231f;
  --ink-soft: #51564f;
  --line: rgba(32, 35, 31, .22);
  --accent: #b5321f;
  --sage: #666b5d;
  --white: #fff;
  --max: 1440px;
  --page-progress: 0;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: inherit; }
button, input, textarea, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--white);
  transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 82px;
  padding: 14px clamp(24px, 4vw, 72px);
  border-bottom: 1px solid transparent;
  transition: background .25s ease, border-color .25s ease;
}
.site-header.is-scrolled { background: rgba(243, 240, 233, .94); border-color: var(--line); backdrop-filter: blur(16px); }
.site-header::after { content: ""; position: absolute; inset: auto 0 -1px; height: 3px; background: var(--accent); transform: scaleX(var(--page-progress)); transform-origin: left; pointer-events: none; }
.brand { display: flex; align-items: center; gap: 13px; text-decoration: none; min-width: 0; }
.brand-mark { width: 46px; height: 38px; flex: 0 0 auto; }
.brand-copy { display: grid; line-height: 1.25; }
.brand-copy strong { font-size: 17px; letter-spacing: .02em; }
.brand-copy small { color: var(--ink-soft); font-size: 10px; letter-spacing: .22em; margin-top: 4px; }
.site-nav { display: flex; align-items: center; gap: clamp(22px, 2.4vw, 44px); }
.site-nav a { position: relative; display: inline-flex; align-items: center; min-height: 44px; font-size: 14px; text-decoration: none; }
.site-nav a:not(.nav-cta)::after { content: ""; position: absolute; inset: auto 0 -8px; height: 2px; background: var(--accent); transform: scaleX(0); transform-origin: left; transition: transform .2s ease; }
.site-nav a:hover::after, .site-nav a[aria-current]::after { transform: scaleX(1); }
.nav-cta { padding: 11px 18px; border: 1px solid var(--ink); }
.nav-cta:hover { background: var(--ink); color: var(--paper); }
.menu-toggle { display: none; min-width: 48px; min-height: 48px; border: 0; background: transparent; color: var(--ink); }

.hero {
  min-height: 100svh;
  max-width: var(--max);
  margin: 0 auto;
  padding: 132px clamp(24px, 5vw, 78px) 38px;
  display: grid;
  grid-template-columns: minmax(360px, .82fr) minmax(560px, 1.35fr);
  grid-template-rows: 1fr auto;
  gap: 32px clamp(38px, 6vw, 90px);
  align-items: center;
  position: relative;
  overflow: hidden;
}
.hero::before { content: ""; position: absolute; width: 52vw; aspect-ratio: 1; right: -22vw; top: -26vw; border: 1px solid var(--line); border-radius: 50%; pointer-events: none; }
.eyebrow { margin: 0 0 18px; color: var(--accent); font: 700 11px/1.2 ui-monospace, SFMono-Regular, Consolas, monospace; letter-spacing: .18em; }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 28px; font-size: clamp(46px, 5.15vw, 78px); line-height: 1.1; letter-spacing: -.055em; font-weight: 800; }
.hero-lead { max-width: 580px; color: var(--ink-soft); font-size: clamp(16px, 1.25vw, 19px); }
.hero-actions { display: flex; align-items: center; gap: 28px; margin-top: 38px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 50px; padding: 13px 24px; border: 1px solid var(--ink); text-decoration: none; cursor: pointer; }
.button-primary { background: var(--ink); color: var(--paper-light); }
.button-primary:hover { background: var(--accent); border-color: var(--accent); }
.text-link { display: inline-flex; align-items: center; min-height: 44px; text-underline-offset: 6px; }
.hero-specimen { margin: 0; position: relative; min-height: 470px; }
.hero-specimen img { width: 100%; height: 470px; object-fit: cover; object-position: center; filter: saturate(.82) contrast(1.04); clip-path: polygon(0 13%, 100% 0, 100% 90%, 5% 100%); }
.hero-specimen figcaption { position: absolute; inset: auto 2% 2% auto; background: rgba(243, 240, 233, .92); padding: 9px 12px 9px 15px; display: grid; font: 10px/1.55 ui-monospace, monospace; letter-spacing: .08em; }
.hero-specimen figcaption::before { content: ""; position: absolute; inset: 0 auto 0 0; width: 3px; background: var(--accent); }
.material-index { grid-column: 1 / -1; display: grid; grid-template-columns: repeat(6, 1fr); border-block: 1px solid var(--line); }
.material-index a { min-height: 76px; padding: 14px 15px; border-right: 1px solid var(--line); text-decoration: none; display: grid; gap: 3px; align-content: center; font-weight: 600; }
.material-index a:last-child { border-right: 0; }
.material-index span { color: var(--accent); font: 10px/1 ui-monospace, monospace; }
.material-index a:hover { background: var(--ink); color: var(--paper); }
.material-index a[aria-current] { background: var(--ink); color: var(--paper); }
.material-index a[aria-current] span { color: #ef8c78; }
.scroll-cue { position: absolute; right: 20px; bottom: 130px; writing-mode: vertical-rl; color: var(--ink-soft); font-size: 10px; letter-spacing: .18em; }
.scroll-cue span { display: inline-block; height: 70px; width: 1px; background: var(--accent); margin-bottom: 12px; transform-origin: top; animation: pulse-line 2s ease-in-out infinite; }

.materials { border-top: 1px solid var(--line); }
.section-intro { max-width: var(--max); margin: 0 auto; padding: 110px clamp(24px, 7vw, 110px); display: grid; grid-template-columns: 1fr 1.4fr .9fr; gap: 54px; align-items: start; }
.section-intro .eyebrow { margin-top: 10px; }
h2 { font-size: clamp(38px, 4.5vw, 68px); line-height: 1.08; letter-spacing: -.045em; }
.section-intro > p:last-child, .path-heading > p:last-child { color: var(--ink-soft); }
.material-sheet { min-height: 540px; display: grid; grid-template-columns: 90px minmax(280px, .72fr) 1.45fr; border-top: 1px solid var(--line); overflow: hidden; }
.sheet-number { padding: 42px 24px; color: var(--accent); font: 700 13px/1 ui-monospace, monospace; border-right: 1px solid var(--line); }
.sheet-copy { padding: clamp(56px, 7vw, 110px) clamp(30px, 5vw, 80px); display: flex; flex-direction: column; justify-content: center; }
.sheet-type { color: var(--sage); font: 700 11px/1 ui-monospace, monospace; letter-spacing: .16em; }
.sheet-copy h3 { font-size: clamp(38px, 4.5vw, 66px); line-height: 1; letter-spacing: -.04em; }
.sheet-copy p { color: var(--ink-soft); max-width: 460px; }
.sheet-copy a { align-self: flex-start; display: inline-flex; align-items: center; min-height: 44px; margin-top: 18px; text-underline-offset: 7px; }
.material-sheet figure { margin: 0; min-height: 540px; overflow: hidden; }
.material-sheet figure img { width: 100%; height: 100%; object-fit: cover; transition: transform .8s cubic-bezier(.2,.7,.2,1); }
.material-sheet:hover figure img { transform: scale(1.025); }
.material-sheet-dark { background: var(--ink); color: var(--paper); }
.material-sheet-dark .sheet-number { border-color: rgba(255,255,255,.18); }
.material-sheet-dark .sheet-copy p, .material-sheet-dark .sheet-type { color: #c3c6bd; }
.material-sheet-accent { background: #a92f1e; color: var(--paper-light); }
.material-sheet-accent .sheet-number { color: var(--paper-light); border-color: rgba(255,255,255,.35); }
.material-sheet-accent .sheet-copy p, .material-sheet-accent .sheet-type { color: #f3d8d0; }

.path { max-width: var(--max); margin: 0 auto; padding: 120px clamp(24px, 7vw, 110px); display: grid; grid-template-columns: .8fr 1.2fr; gap: clamp(60px, 8vw, 130px); }
.path-heading { position: sticky; top: 130px; align-self: start; }
.path-rail { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--ink); }
.path-rail li { display: grid; grid-template-columns: 78px 1fr; gap: 28px; padding: 34px 0; border-bottom: 1px solid var(--line); position: relative; }
.path-rail li::after { content: ""; position: absolute; width: 100%; height: 3px; left: 0; bottom: -1px; background: var(--accent); transform: scaleX(0); transform-origin: left; transition: transform .5s ease; }
.path-rail li:hover::after { transform: scaleX(1); }
.path-rail li > span { color: var(--accent); font: 700 24px/1 ui-monospace, monospace; }
.path-rail h3 { font-size: 25px; margin-bottom: 8px; }
.path-rail p { color: var(--ink-soft); margin-bottom: 0; }

.manufacturing { min-height: 760px; display: grid; grid-template-columns: 1.35fr .85fr; background: var(--ink); color: var(--paper-light); }
.manufacturing-visual { margin: 0; position: relative; min-height: 760px; overflow: hidden; }
.manufacturing-visual img { width: 100%; height: 100%; object-fit: cover; filter: saturate(.72) contrast(1.05); }
.manufacturing-visual::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, transparent 58%, rgba(32,35,31,.74)); }
.manufacturing-visual figcaption { position: absolute; left: 32px; bottom: 30px; z-index: 1; font: 11px/1 ui-monospace, monospace; letter-spacing: .15em; }
.manufacturing-copy { padding: 110px clamp(38px, 6vw, 96px); align-self: center; }
.manufacturing-copy p:not(.eyebrow) { color: #c5c8c0; }
.manufacturing-copy address { margin-top: 48px; padding-top: 28px; border-top: 1px solid rgba(255,255,255,.22); font-style: normal; font-size: 17px; }
.manufacturing-copy address span { display: block; color: #a9ad9e; font: 10px/1 ui-monospace, monospace; letter-spacing: .18em; margin-bottom: 12px; }

.signals { max-width: var(--max); margin: 0 auto; padding: 120px clamp(24px, 7vw, 110px); }
.signals-intro { display: grid; grid-template-columns: .62fr 1.38fr; gap: 50px; margin-bottom: 70px; }
.signal-list { border-top: 1px solid var(--ink); }
.signal-list article { display: grid; grid-template-columns: 120px 1fr auto; gap: 36px; align-items: center; min-height: 170px; padding: 30px 0; border-bottom: 1px solid var(--line); }
.signal-year { margin: 0; color: var(--accent); font: 700 28px/1 ui-monospace, monospace; }
.signal-list h3 { margin-bottom: 8px; font-size: 24px; }
.signal-list p:not(.signal-year) { margin-bottom: 0; color: var(--ink-soft); }
.signal-list a { display: inline-flex; align-items: center; min-height: 44px; font-size: 13px; text-underline-offset: 6px; white-space: nowrap; }

.contact { display: grid; grid-template-columns: .85fr 1.15fr; gap: clamp(54px, 8vw, 130px); padding: 120px clamp(24px, 7vw, 110px); background: #d8d4ca; }
.contact-copy > p:not(.eyebrow):not(.contact-address) { max-width: 560px; color: var(--ink-soft); }
.contact-address { margin-top: 48px; padding-top: 25px; border-top: 1px solid var(--line); }
.contact-address span { display: block; margin-bottom: 8px; color: var(--accent); font: 700 10px/1 ui-monospace, monospace; letter-spacing: .15em; }
.contact-form { border-top: 1px solid var(--ink); padding-top: 30px; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.contact-form label { display: grid; gap: 8px; margin-bottom: 22px; font-size: 13px; }
.contact-form input, .contact-form select, .contact-form textarea { width: 100%; border: 0; border-bottom: 1px solid var(--ink); border-radius: 0; background: transparent; min-height: 48px; padding: 10px 2px; color: var(--ink); }
.contact-form textarea { resize: vertical; }
.contact-form input:focus, .contact-form select:focus, .contact-form textarea:focus { outline: 0; border-bottom-color: transparent; box-shadow: inset 0 -3px var(--accent); }
.form-footer { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-top: 16px; }
.form-status { margin: 0; color: #722519; font-weight: 600; }

.site-footer { display: grid; grid-template-columns: 1.5fr 1fr 1fr auto; gap: 36px; align-items: center; min-height: 120px; padding: 32px clamp(24px, 5vw, 78px); background: var(--ink); color: #bfc3ba; font-size: 12px; }
.site-footer p { margin: 0; }
.footer-brand { color: var(--paper-light); font-size: 15px; font-weight: 700; }
.site-footer a { display: inline-flex; align-items: center; min-height: 44px; text-underline-offset: 5px; }

@keyframes pulse-line { 0%,100% { transform: scaleY(.35); opacity: .45; } 50% { transform: scaleY(1); opacity: 1; } }

@media (max-width: 1080px) {
  .site-header { min-height: 74px; }
  .brand-copy strong { font-size: 15px; }
  .brand-copy small { display: none; }
  .site-nav { gap: 22px; }
  .hero { padding-top: 112px; grid-template-columns: 1fr 1.1fr; }
  .hero-specimen, .hero-specimen img { min-height: 380px; height: 380px; }
  .section-intro { grid-template-columns: .5fr 1.3fr 1fr; gap: 34px; }
  .material-sheet { grid-template-columns: 70px .8fr 1fr; }
  .sheet-copy { padding-inline: 38px; }
  .path { gap: 60px; }
  .manufacturing { grid-template-columns: 1.1fr .9fr; }
}

@media (max-width: 820px) {
  .menu-toggle { display: inline-flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px; cursor: pointer; }
  .menu-toggle-label { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
  .menu-toggle-lines, .menu-toggle-lines::before, .menu-toggle-lines::after { display: block; width: 24px; height: 2px; background: currentColor; transition: transform .2s ease; }
  .menu-toggle-lines { position: relative; }
  .menu-toggle-lines::before, .menu-toggle-lines::after { content: ""; position: absolute; left: 0; }
  .menu-toggle-lines::before { top: -7px; }
  .menu-toggle-lines::after { top: 7px; }
  .menu-open .menu-toggle-lines { background: transparent; }
  .menu-open .menu-toggle-lines::before { transform: translateY(7px) rotate(45deg); }
  .menu-open .menu-toggle-lines::after { transform: translateY(-7px) rotate(-45deg); }
  .site-nav { position: fixed; inset: 74px 0 auto; display: grid; gap: 0; background: var(--paper); border-bottom: 1px solid var(--ink); transform: translateY(-140%); visibility: hidden; pointer-events: none; transition: transform .25s ease, visibility 0s linear .25s; }
  .menu-open .site-nav { transform: translateY(0); visibility: visible; pointer-events: auto; transition-delay: 0s; }
  .site-nav a { min-height: 58px; display: flex; align-items: center; padding: 10px 24px; border-top: 1px solid var(--line); }
  .nav-cta { border: 0; background: var(--ink); color: var(--paper); }
  .hero { grid-template-columns: 1fr; grid-template-rows: auto auto auto; gap: 28px; padding-top: 116px; }
  .hero-copy { max-width: 720px; }
  .hero-specimen { min-height: 360px; }
  .material-index { grid-template-columns: repeat(3, 1fr); }
  .material-index a:nth-child(3) { border-right: 0; }
  .material-index a:nth-child(-n+3) { border-bottom: 1px solid var(--line); }
  .scroll-cue { display: none; }
  .section-intro { grid-template-columns: 1fr; }
  .section-intro > p:last-child { max-width: 620px; }
  .material-sheet { grid-template-columns: 64px 1fr; }
  .material-sheet figure { grid-column: 1 / -1; min-height: 420px; order: -1; }
  .sheet-number { grid-column: 1; }
  .sheet-copy { grid-column: 2; padding-block: 58px; }
  .path { grid-template-columns: 1fr; }
  .path-heading { position: static; }
  .manufacturing { grid-template-columns: 1fr; }
  .manufacturing-visual { min-height: 520px; }
  .manufacturing-copy { padding-block: 80px; }
  .signals-intro { grid-template-columns: 1fr; gap: 10px; }
  .signal-list article { grid-template-columns: 90px 1fr; }
  .signal-list a { grid-column: 2; }
  .contact { grid-template-columns: 1fr; }
  .site-footer { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 520px) {
  .site-header { padding-inline: 16px; }
  .brand-mark { width: 38px; }
  .brand-copy strong { max-width: 220px; font-size: 13px; }
  .hero { padding: 106px 18px 24px; }
  h1 { font-size: clamp(40px, 12vw, 54px); }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 18px; }
  .hero-specimen, .hero-specimen img { min-height: 290px; height: 290px; }
  .material-index { grid-template-columns: repeat(2, 1fr); }
  .material-index a { min-height: 68px; border-bottom: 1px solid var(--line); }
  .material-index a:nth-child(odd) { border-right: 1px solid var(--line); }
  .material-index a:nth-child(even) { border-right: 0; }
  .material-index a:nth-last-child(-n+2) { border-bottom: 0; }
  .section-intro, .path, .signals, .contact { padding: 84px 20px; }
  .material-sheet { display: flex; flex-direction: column; min-height: 0; }
  .material-sheet figure { order: 0; min-height: 300px; height: 300px; }
  .sheet-number { padding: 24px 20px 0; border-right: 0; }
  .sheet-copy { padding: 32px 20px 54px; }
  .sheet-copy h3 { font-size: 46px; }
  .path-rail li { grid-template-columns: 52px 1fr; gap: 16px; }
  .manufacturing-visual { min-height: 390px; }
  .manufacturing-copy { padding: 76px 20px; }
  .signal-list article { grid-template-columns: 1fr; gap: 10px; }
  .signal-list a { grid-column: 1; }
  .field-row { grid-template-columns: 1fr; gap: 0; }
  .form-footer { align-items: stretch; flex-direction: column; }
  .form-footer .button { width: 100%; }
  .site-footer { grid-template-columns: 1fr; gap: 14px; padding: 44px 20px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}