/* =========================================================
   LINGHAO OPTOELECTRONICS
   Gallery / precision-manufacturing visual system
   ========================================================= */

@font-face {
  font-family: "Instrument Serif";
  src: url("../fonts/instrument-serif-400.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Instrument Serif";
  src: url("../fonts/instrument-serif-400-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: "Archivo";
  src: url("../fonts/archivo-var.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

:root {
  --paper: #f4ede3;
  --paper-2: #fbf7f0;
  --paper-3: #efe6d9;
  --ink: #14171a;
  --muted: #6d6a63;
  --line: rgba(20, 23, 26, 0.14);
  --line-strong: rgba(20, 23, 26, 0.3);
  --blue: #0b3fe8;
  --blue-light: #b9c9ff;
  --blue-soft: #dce6f5;
  --oak: #a5794f;
  --night: #101315;
  --night-2: #191d20;
  --serif: "Instrument Serif", "Songti SC", "STSong", "SimSun", "Noto Serif SC", serif;
  --sans: "Archivo", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --header-h: 76px;
  --pad: clamp(20px, 4.5vw, 72px);
  --maxw: 1360px;
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
}

*,
*::before,
*::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 24px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: clip;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  opacity: 0.028;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.82' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.6'/%3E%3C/svg%3E");
}

body.menu-open { overflow: hidden; }

::selection { background: var(--blue); color: var(--paper); }

::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--paper); }
::-webkit-scrollbar-thumb {
  background: #c9bfaf;
  border: 2px solid var(--paper);
  border-radius: 999px;
}

img { max-width: 100%; }
a { color: inherit; }
button, input, textarea { font: inherit; }

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
}
.contact-section :focus-visible { outline-color: var(--paper); }

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding-left: var(--pad);
  padding-right: var(--pad);
}

h1, h2, h3, p, figure, dl, dd { margin: 0; }
ul { padding: 0; }

em { font-style: italic; }

/* ---------- scroll progress ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 101;
  pointer-events: none;
}
.scroll-progress span {
  display: block;
  height: 100%;
  background: var(--blue);
  transform: scaleX(0);
  transform-origin: left center;
  will-change: transform;
}

/* ---------- header ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 28px;
  padding: 0 var(--pad);
  background: rgba(244, 237, 227, 0.88);
  backdrop-filter: blur(16px) saturate(1.1);
  -webkit-backdrop-filter: blur(16px) saturate(1.1);
  border-bottom: 1px solid transparent;
  transition: background 0.35s var(--ease), border-color 0.35s var(--ease), box-shadow 0.35s var(--ease);
}
.site-header.is-scrolled {
  background: rgba(244, 237, 227, 0.97);
  border-bottom-color: var(--line);
  box-shadow: 0 18px 40px rgba(20, 23, 26, 0.045);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
  flex-shrink: 0;
}
.brand-mark {
  width: 28px;
  height: 28px;
  display: block;
  color: var(--ink);
  flex-shrink: 0;
}
.brand-accent { fill: var(--blue); }
.brand-text { display: flex; flex-direction: column; gap: 3px; }
.brand-name {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.24em;
  line-height: 1;
}
.brand-sub {
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0.23em;
  color: var(--muted);
  line-height: 1;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(16px, 2vw, 30px);
  margin-left: auto;
  font-size: 12.5px;
  letter-spacing: 0.015em;
  color: var(--muted);
}
.site-nav a {
  position: relative;
  text-decoration: none;
  padding: 6px 0;
  white-space: nowrap;
  transition: color 0.25s ease;
}
.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 1px;
  height: 1px;
  background: var(--blue);
  transform: scaleX(0);
  transform-origin: right center;
  transition: transform 0.35s var(--ease);
}
.site-nav a:hover,
.site-nav a.is-active { color: var(--ink); }
.site-nav a:hover::after,
.site-nav a.is-active::after {
  transform: scaleX(1);
  transform-origin: left center;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-left: 10px;
  flex-shrink: 0;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--muted);
  white-space: nowrap;
}
.lang-btn {
  appearance: none;
  border: 0;
  background: none;
  padding: 4px 0;
  color: inherit;
  cursor: pointer;
  letter-spacing: inherit;
  border-bottom: 1px solid transparent;
  transition: color 0.25s ease, border-color 0.25s ease;
}
.lang-btn.is-active {
  color: var(--ink);
  border-bottom-color: var(--ink);
}
.lang-btn:hover { color: var(--ink); }
.lang-divider { opacity: 0.35; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 48px;
  padding: 0 26px;
  border: 1px solid transparent;
  border-radius: 2px;
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.02em;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: background 0.3s var(--ease), color 0.3s var(--ease), border-color 0.3s var(--ease), transform 0.3s var(--ease);
}
.btn-primary {
  background: var(--blue);
  color: var(--paper);
}
.btn-primary:hover {
  background: var(--ink);
  transform: translateY(-1px);
}
.btn-light {
  background: var(--paper);
  color: var(--blue);
}
.btn-light:hover {
  background: var(--ink);
  color: var(--paper);
  transform: translateY(-1px);
}
.header-cta { height: 42px; padding: 0 20px; font-size: 11.5px; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  width: fit-content;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--line-strong);
  color: var(--ink);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.3s ease, border-color 0.3s ease, gap 0.3s var(--ease);
}
.link-arrow span { transition: transform 0.3s var(--ease); }
.link-arrow:hover {
  color: var(--blue);
  border-color: var(--blue);
  gap: 12px;
}
.link-arrow:hover span { transform: translateY(2px); }

.menu-toggle {
  display: none;
  appearance: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  padding: 0;
  position: relative;
}
.menu-toggle span {
  position: absolute;
  left: 12px;
  right: 12px;
  height: 1px;
  background: var(--ink);
  transition: transform 0.35s var(--ease), top 0.35s var(--ease);
}
.menu-toggle span:first-child { top: 17px; }
.menu-toggle span:last-child { top: 24px; }
.menu-toggle[aria-expanded="true"] span:first-child { top: 21px; transform: rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:last-child { top: 21px; transform: rotate(-45deg); }

/* ---------- mobile menu ---------- */
.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: calc(var(--header-h) + 22px) var(--pad) 34px;
  background: var(--paper);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  overflow-y: auto;
  transition: opacity 0.35s var(--ease), visibility 0.35s var(--ease);
}
.mobile-menu.is-open {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}
.mobile-nav { display: flex; flex-direction: column; }
.mobile-nav a {
  display: flex;
  align-items: baseline;
  gap: 18px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  font-family: var(--serif);
  font-size: clamp(30px, 6.4vw, 44px);
  line-height: 1.05;
  letter-spacing: -0.01em;
  text-decoration: none;
  color: var(--ink);
}
.m-num {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--muted);
}
.mobile-menu-foot {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-top: 40px;
}
.mobile-email {
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
}

/* ---------- hero ---------- */
.hero {
  padding-top: var(--header-h);
  background: var(--paper);
}
.hero-copy {
  padding-top: clamp(44px, 6.2vw, 94px);
  padding-bottom: clamp(36px, 4.6vw, 60px);
}
.hero-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 40px;
  align-items: end;
}
.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 10.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}
.eyebrow-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--blue);
  flex-shrink: 0;
}
.hero h1 {
  margin-top: clamp(18px, 2.4vw, 32px);
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(54px, 7vw, 112px);
  line-height: 0.94;
  letter-spacing: -0.025em;
  max-width: 17ch;
}
.hero h1 em {
  color: var(--blue);
  font-style: italic;
}
.h1-line { display: inline-block; }

.hero-aside {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 5px;
  padding-left: 18px;
  border-left: 1px solid var(--line-strong);
  padding-bottom: 8px;
  min-width: 176px;
}
.aside-index {
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--blue);
}
.aside-name { font-size: 13px; font-weight: 500; }
.aside-meta { font-size: 10.5px; letter-spacing: 0.08em; color: var(--muted); }

.hero-foot {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 48px;
  margin-top: clamp(30px, 4vw, 54px);
}
.hero-lede {
  max-width: 52ch;
  font-size: clamp(15.5px, 1.2vw, 18px);
  line-height: 1.65;
  color: var(--muted);
}
.hero-actions {
  display: flex;
  align-items: center;
  gap: 28px;
  flex-shrink: 0;
}

.hero-media {
  position: relative;
  height: clamp(440px, 62vh, 720px);
  overflow: hidden;
  background: var(--paper);
}
.hero-media picture {
  position: absolute;
  inset: 0;
  display: block;
}
.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 45%;
  display: block;
}
.hero-media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  box-shadow: inset 0 0 120px rgba(20, 23, 26, 0.08);
}
.hero-caption {
  position: absolute;
  top: 22px;
  left: var(--pad);
  z-index: 2;
  padding: 7px 11px;
  background: rgba(16, 19, 21, 0.42);
  color: rgba(244, 237, 227, 0.92);
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.scroll-cue {
  position: absolute;
  right: var(--pad);
  bottom: 104px;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  font-size: 9.5px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink);
}
.scroll-line {
  width: 1px;
  height: 54px;
  background: currentColor;
  transform-origin: top center;
  animation: scrollLine 2.4s ease-in-out infinite;
}
@keyframes scrollLine {
  0%, 100% { transform: scaleY(0.35); opacity: 0.4; }
  45% { transform: scaleY(1); opacity: 1; }
}

.spec-rail-wrap {
  position: relative;
  z-index: 3;
  margin-top: -70px;
}
.spec-rail {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  background: rgba(251, 247, 240, 0.96);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--line);
  box-shadow: 0 26px 60px rgba(20, 23, 26, 0.09);
}
.rail-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 20px 26px 22px;
  border-right: 1px solid var(--line);
}
.rail-item:last-child { border-right: 0; }
.rail-label {
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}
.rail-value {
  font-family: var(--serif);
  font-size: clamp(22px, 2vw, 28px);
  line-height: 1.1;
  letter-spacing: -0.01em;
}
.rail-note { font-size: 10.5px; color: var(--muted); }

/* ---------- shared section ---------- */
.section { padding: clamp(78px, 9vw, 138px) 0; }
.section-head {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  gap: clamp(32px, 6vw, 96px);
  align-items: end;
  margin-bottom: clamp(44px, 6vw, 82px);
}
.section-label {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}
.section-label span:first-child {
  color: var(--blue);
  font-variant-numeric: tabular-nums;
}
.section-label::after {
  content: "";
  width: 30px;
  height: 1px;
  background: currentColor;
  opacity: 0.4;
}
.section-label.light { color: rgba(244, 237, 227, 0.55); }
.section-label.light span:first-child { color: var(--blue-light); }

.section h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(42px, 5vw, 76px);
  line-height: 1;
  letter-spacing: -0.022em;
}
.section h2 em { color: var(--blue); font-style: italic; }

.section-lede {
  max-width: 46ch;
  font-size: clamp(15.5px, 1.25vw, 18px);
  line-height: 1.65;
  color: var(--muted);
}
.section-lede.light { color: rgba(244, 237, 227, 0.68); }

/* ---------- product ---------- */
.product-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: clamp(38px, 5vw, 88px);
  align-items: center;
}
.product-figure { overflow: hidden; }
.product-figure img {
  display: block;
  width: 100%;
  height: auto;
}
.product-copy {
  display: flex;
  flex-direction: column;
  gap: 22px;
}
.model-line {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding-bottom: 13px;
  border-bottom: 1px solid var(--line-strong);
  font-size: 10px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--muted);
}
.model-line span:last-child { color: var(--ink); letter-spacing: 0.06em; }
.product-copy > p {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.7;
}
.product-facts {
  border-top: 1px solid var(--line);
  margin: 6px 0;
}
.product-facts div {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
}
.product-facts dt {
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  flex-shrink: 0;
}
.product-facts dd {
  font-size: 13.5px;
  text-align: right;
  line-height: 1.5;
}

.detail-band {
  position: relative;
  margin-top: clamp(42px, 6vw, 86px);
  overflow: hidden;
  background: var(--night);
}
.detail-band img {
  display: block;
  width: 100%;
  height: clamp(190px, 26vw, 340px);
  object-fit: cover;
  object-position: center 46%;
}
.detail-band::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  height: 52%;
  background: linear-gradient(to top, rgba(8, 10, 11, 0.66), rgba(8, 10, 11, 0));
  pointer-events: none;
}
.detail-band figcaption {
  position: absolute;
  left: clamp(18px, 2.6vw, 32px);
  right: clamp(18px, 2.6vw, 32px);
  bottom: clamp(16px, 2.2vw, 26px);
  z-index: 1;
  display: flex;
  align-items: baseline;
  gap: 14px;
  color: var(--paper);
  font-size: clamp(11px, 0.95vw, 12.5px);
  letter-spacing: 0.02em;
}
.detail-index {
  font-size: 9.5px;
  letter-spacing: 0.16em;
  color: var(--blue-light);
}

/* ---------- features ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.feature {
  display: flex;
  flex-direction: column;
  min-height: 272px;
  padding: clamp(22px, 2.2vw, 34px);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  transition: background 0.4s var(--ease);
}
.feature:hover { background: var(--paper-2); }
.feature-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: clamp(40px, 4vw, 56px);
}
.feature-icon {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--blue-soft);
  color: var(--ink);
  border: 1px solid transparent;
  transition: background 0.35s var(--ease), color 0.35s var(--ease), transform 0.35s var(--ease);
}
.feature-icon svg { width: 22px; height: 22px; }
.feature:hover .feature-icon {
  background: var(--blue);
  color: var(--paper);
  transform: translateY(-2px);
}
.feature-num {
  font-size: 9.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
}
.feature h3 {
  margin-top: 26px;
  font-size: 16.5px;
  font-weight: 500;
  letter-spacing: -0.01em;
}
.feature p {
  margin-top: 7px;
  max-width: 30ch;
  font-size: 13px;
  line-height: 1.62;
  color: var(--muted);
}

/* ---------- dark section ---------- */
.dark-section {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  min-height: 680px;
  background: var(--night);
  color: var(--paper);
}
.dark-media { position: relative; overflow: hidden; }
.dark-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.dark-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: clamp(54px, 6vw, 100px) clamp(30px, 4.5vw, 76px);
}
.dark-copy h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(42px, 4.6vw, 70px);
  line-height: 1.02;
  letter-spacing: -0.02em;
}
.dark-copy h2 em { color: var(--blue-light); }
.dark-copy .section-lede { margin-top: 24px; }
.dark-list {
  list-style: none;
  margin: 30px 0 0;
  border-top: 1px solid rgba(244, 237, 227, 0.16);
}
.dark-list li {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 13px 0;
  border-bottom: 1px solid rgba(244, 237, 227, 0.16);
}
.dark-list-label {
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(244, 237, 227, 0.5);
  flex-shrink: 0;
}
.dark-list-value { font-size: 13px; color: rgba(244, 237, 227, 0.9); text-align: right; }
.dark-quote {
  margin-top: 36px;
  padding-left: 22px;
  border-left: 2px solid var(--blue-light);
  max-width: 30ch;
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(22px, 2vw, 30px);
  line-height: 1.38;
  color: var(--paper);
}

/* ---------- spaces ---------- */
.spaces-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(16px, 2vw, 28px);
}
.space-card { margin: 0; }
.space-media {
  overflow: hidden;
  aspect-ratio: 1024 / 1212;
  background: var(--paper-3);
}
.space-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 1.1s var(--ease);
}
.space-card:hover .space-media img { transform: scale(1.035); }
.space-card figcaption {
  display: flex;
  flex-direction: column;
  gap: 5px;
  margin-top: 15px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}
.space-title {
  font-size: 14.5px;
  font-weight: 500;
  transition: color 0.3s ease;
}
.space-card:hover .space-title { color: var(--blue); }
.space-meta { font-size: 12px; line-height: 1.5; color: var(--muted); }

/* ---------- commercial ---------- */
.commercial {
  position: relative;
  display: flex;
  align-items: flex-end;
  min-height: clamp(560px, 82vh, 820px);
  overflow: hidden;
  color: var(--paper);
}
.commercial-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.commercial-shade {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(9, 11, 13, 0.8) 0%, rgba(9, 11, 13, 0.48) 44%, rgba(9, 11, 13, 0.08) 78%, rgba(9, 11, 13, 0.22) 100%),
    linear-gradient(0deg, rgba(9, 11, 13, 0.52) 0%, rgba(9, 11, 13, 0) 55%);
}
.commercial-content {
  position: relative;
  z-index: 2;
  padding-top: 150px;
  padding-bottom: clamp(48px, 6vw, 86px);
}
.commercial h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(50px, 6vw, 94px);
  line-height: 0.98;
  letter-spacing: -0.025em;
}
.commercial h2 em { color: var(--blue-light); }
.commercial-lede {
  margin-top: 24px;
  max-width: 52ch;
  font-size: clamp(15px, 1.2vw, 17px);
  line-height: 1.65;
  color: rgba(244, 237, 227, 0.78);
}
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
  margin: 28px 0 0;
}
.tag-list li {
  padding: 7px 13px;
  border: 1px solid rgba(244, 237, 227, 0.3);
  font-size: 9.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* ---------- specs ---------- */
.specs-section { border-top: 1px solid var(--line); }
.specs-grid {
  display: grid;
  grid-template-columns: 0.72fr 1.28fr;
  gap: clamp(38px, 6vw, 96px);
  align-items: start;
}
.specs-intro {
  position: sticky;
  top: calc(var(--header-h) + 38px);
}
.specs-intro h2 { margin-bottom: 26px; }
.spec-note {
  margin-top: 30px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  max-width: 34ch;
  font-size: 11.5px;
  line-height: 1.65;
  color: var(--muted);
}
.spec-groups {
  columns: 2;
  column-gap: clamp(28px, 3.6vw, 52px);
}
.spec-group {
  break-inside: avoid;
  margin-bottom: 38px;
}
.spec-group h3 {
  margin-bottom: 11px;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--blue);
}
.spec-group dl { border-top: 1px solid var(--line-strong); }
.spec-group dl div {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}
.spec-group dt {
  flex-shrink: 0;
  max-width: 42%;
  font-size: 12px;
  color: var(--muted);
}
.spec-group dd {
  font-size: 12.5px;
  line-height: 1.45;
  text-align: right;
}

/* ---------- company ---------- */
.company-section {
  background: var(--paper-2);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.company-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(46px, 7vw, 120px);
  align-items: start;
}
.company-copy h2 { margin-bottom: 26px; }
.company-copy > p:not(.section-label):not(.section-lede):not(.coords) {
  margin-top: 20px;
  max-width: 48ch;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--muted);
}
.coords {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 40px;
  padding-top: 17px;
  border-top: 1px solid var(--line);
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}
.capabilities { border-top: 1px solid var(--line-strong); }
.capability {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 18px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}
.cap-num {
  font-family: var(--serif);
  font-size: 26px;
  line-height: 1;
  color: var(--blue);
}
.capability h3 { font-size: 17px; font-weight: 500; letter-spacing: -0.01em; }
.capability p {
  margin-top: 6px;
  max-width: 38ch;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- contact ---------- */
.contact-section {
  background: var(--blue);
  color: var(--paper);
  padding: clamp(78px, 9vw, 138px) 0;
}
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 0.9fr;
  gap: clamp(44px, 7vw, 110px);
  align-items: start;
}
.contact-copy h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(46px, 5.4vw, 84px);
  line-height: 1;
  letter-spacing: -0.025em;
}
.contact-copy h2 em { color: #c9d6ff; }
.contact-lede {
  margin-top: 26px;
  max-width: 44ch;
  font-size: 15.5px;
  line-height: 1.65;
  color: rgba(244, 237, 227, 0.76);
}
.contact-meta {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-top: 46px;
}
.meta-label {
  display: block;
  margin-bottom: 7px;
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(244, 237, 227, 0.64);
}
.contact-email {
  display: inline-block;
  padding-bottom: 5px;
  border-bottom: 1px solid rgba(244, 237, 227, 0.4);
  font-family: var(--serif);
  font-size: clamp(25px, 2.9vw, 38px);
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--paper);
  text-decoration: none;
  transition: border-color 0.3s ease;
}
.contact-email:hover { border-color: var(--paper); }
.meta-value { font-size: 14px; color: rgba(244, 237, 227, 0.86); }

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 21px;
  padding-top: 6px;
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 21px;
}
.contact-form label { display: block; }
.contact-form label > span {
  display: block;
  margin-bottom: 7px;
  font-size: 9.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: rgba(244, 237, 227, 0.64);
}
.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 9px 0 11px;
  border: 0;
  border-bottom: 1px solid rgba(244, 237, 227, 0.4);
  border-radius: 0;
  background: transparent;
  color: var(--paper);
  font-size: 15.5px;
  line-height: 1.5;
  transition: border-color 0.3s ease;
}
.contact-form textarea { min-height: 108px; resize: vertical; }
.contact-form input:focus,
.contact-form textarea:focus {
  border-bottom-color: var(--paper);
  outline: none;
}
.contact-form input:focus-visible,
.contact-form textarea:focus-visible {
  outline: 1px solid rgba(244, 237, 227, 0.55);
  outline-offset: 3px;
}
.contact-form .btn { align-self: flex-start; margin-top: 4px; }
.form-note {
  max-width: 42ch;
  font-size: 10.5px;
  line-height: 1.6;
  color: rgba(244, 237, 227, 0.64);
}

/* ---------- footer ---------- */
.site-footer {
  padding: clamp(46px, 5.5vw, 76px) 0 26px;
  background: var(--paper);
  border-top: 1px solid var(--line);
}
.footer-top {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 40px;
  align-items: start;
  padding-bottom: 44px;
  border-bottom: 1px solid var(--line);
}
.footer-tagline {
  margin-top: 16px;
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 24px;
  font-size: 12px;
  color: var(--muted);
}
.footer-nav a {
  text-decoration: none;
  transition: color 0.25s ease;
}
.footer-nav a:hover { color: var(--blue); }
.footer-contact {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 7px;
  text-align: right;
  font-size: 11.5px;
  color: var(--muted);
}
.footer-contact > a:first-child {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 2px;
}
.back-top {
  margin-top: 6px;
  font-size: 9.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue);
  text-decoration: none;
}
.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 32px;
  padding-top: 20px;
  font-size: 10px;
  line-height: 1.65;
  color: var(--muted);
}
.footer-bottom p:first-child { max-width: 62ch; }
.footer-bottom p:last-child { max-width: 52ch; text-align: right; }

/* ---------- chinese typography ---------- */
html[lang="zh-CN"] body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", var(--sans);
  letter-spacing: 0.01em;
}
html[lang="zh-CN"] h1,
html[lang="zh-CN"] h2,
html[lang="zh-CN"] .rail-value,
html[lang="zh-CN"] .dark-quote,
html[lang="zh-CN"] .contact-email,
html[lang="zh-CN"] .mobile-nav a {
  font-family: "Songti SC", "STSong", "SimSun", "Noto Serif SC", var(--serif);
  letter-spacing: 0.02em;
}
html[lang="zh-CN"] h1 {
  font-size: clamp(46px, 6vw, 96px);
  line-height: 1.12;
  letter-spacing: 0.01em;
}
html[lang="zh-CN"] h2 { line-height: 1.14; }
html[lang="zh-CN"] h1 em,
html[lang="zh-CN"] h2 em,
html[lang="zh-CN"] .dark-quote,
html[lang="zh-CN"] .mobile-nav a {
  font-style: normal;
}
html[lang="zh-CN"] .hero-lede { max-width: 46ch; }
html[lang="zh-CN"] .hero h1 { max-width: 18ch; }
html[lang="zh-CN"] .section-label,
html[lang="zh-CN"] .rail-label,
html[lang="zh-CN"] .feature-num,
html[lang="zh-CN"] .aside-index,
html[lang="zh-CN"] .coords { letter-spacing: 0.12em; }
html[lang="zh-CN"] .btn { letter-spacing: 0.08em; }

/* ---------- reveal / motion ---------- */
.js .reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
  transition-delay: var(--delay, 0s);
}
.js .reveal.is-visible {
  opacity: 1;
  transform: none;
}

.js .eyebrow,
.js .hero h1,
.js .hero-lede,
.js .hero-actions,
.js .hero-aside,
.js .spec-rail-wrap {
  opacity: 0;
  transform: translateY(18px);
  animation: heroIn 0.95s var(--ease) forwards;
}
.js .eyebrow { animation-delay: 0.08s; }
.js .hero h1 { animation-delay: 0.16s; }
.js .hero-lede { animation-delay: 0.3s; }
.js .hero-actions { animation-delay: 0.38s; }
.js .hero-aside { animation-delay: 0.42s; }
.js .spec-rail-wrap { animation-delay: 0.5s; }
@keyframes heroIn {
  to { opacity: 1; transform: none; }
}
.js .hero-media img {
  animation: mediaIn 1.4s var(--ease) both;
}
@keyframes mediaIn {
  from { opacity: 0; transform: scale(1.025); }
  to { opacity: 1; transform: scale(1); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .js .reveal { opacity: 1; transform: none; }
}

/* =========================================================
   responsive
   ========================================================= */

@media (max-width: 1180px) {
  .site-nav { gap: 16px; font-size: 12px; }
  .header-actions { gap: 14px; }
  .header-cta { padding: 0 16px; }
}

@media (max-width: 1040px) {
  .site-nav { display: none; }
  .menu-toggle { display: block; }
  .header-actions { margin-left: auto; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .feature { min-height: 240px; }
}

@media (max-width: 960px) {
  .hero-head { grid-template-columns: 1fr; }
  .hero-aside {
    display: none;
  }
  .product-grid { grid-template-columns: 1fr; gap: 36px; }
  .product-figure { order: 2; }
  .product-copy { order: 1; }
  .section-head { grid-template-columns: 1fr; gap: 24px; align-items: start; }
  .section-head .section-lede { max-width: 54ch; }
  .hero-media {
    height: auto;
    aspect-ratio: 1536 / 956;
  }
  .spec-rail-wrap { margin-top: -46px; }
  .spec-rail { grid-template-columns: 1fr 1fr; }
  .rail-item:nth-child(2n) { border-right: 0; }
  .rail-item:nth-child(-n + 2) { border-bottom: 1px solid var(--line); }
  .scroll-cue { display: none; }
  .dark-section { grid-template-columns: 1fr; min-height: 0; }
  .dark-media { aspect-ratio: 16 / 10; }
  .dark-copy { padding-top: clamp(48px, 8vw, 76px); padding-bottom: clamp(48px, 8vw, 76px); }
  .specs-grid { grid-template-columns: 1fr; }
  .specs-intro { position: static; }
  .specs-intro h2 br { display: none; }
  .spec-groups { columns: 2; }
  .company-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .contact-copy h2 br { display: none; }
}

@media (max-width: 820px) {
  .hero-foot { flex-direction: column; align-items: flex-start; gap: 28px; }
  .hero-actions { flex-wrap: wrap; gap: 20px; }
  .spaces-grid { grid-template-columns: 1fr; gap: 34px; }
  .space-media { aspect-ratio: 1024 / 1100; }
  .footer-top { grid-template-columns: 1fr 1fr; }
  .footer-nav { justify-content: flex-start; }
  .footer-contact { grid-column: 2; align-items: flex-start; text-align: left; }
  .footer-bottom { flex-direction: column; gap: 14px; }
  .footer-bottom p:last-child { text-align: left; }
}

@media (max-width: 700px) {
  :root { --header-h: 68px; }
  .header-cta { display: none; }
  .form-row { grid-template-columns: 1fr; }
  .contact-form .btn { align-self: stretch; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature { min-height: 0; padding: 26px 24px 30px; }
  .feature-top { margin-bottom: 0; }
  .feature h3 { margin-top: 22px; }
  .feature p { max-width: 36ch; }
  .spec-groups { columns: 1; }
  .spec-group { margin-bottom: 30px; }
  .commercial { min-height: 620px; }
  .commercial-content { padding-top: 110px; }
  .commercial h2 { font-size: clamp(44px, 11vw, 64px); }
  .tag-list li { font-size: 9px; }
  .footer-top { grid-template-columns: 1fr; gap: 30px; }
  .footer-contact { grid-column: auto; }
  .footer-bottom p:last-child { max-width: 100%; }
}

@media (max-width: 620px) {
  .lang-switch { display: none; }
  .mobile-menu-foot .lang-switch { display: inline-flex; }
  .hero h1 { font-size: clamp(46px, 12.4vw, 64px); }
  html[lang="zh-CN"] .hero h1 { font-size: clamp(40px, 10.6vw, 56px); }
  .hero-copy { padding-top: 38px; }
  .hero-lede { font-size: 15px; }
  .spec-rail-wrap { margin-top: -32px; }
  .rail-item { padding: 16px 18px 18px; }
  .rail-value { font-size: 21px; }
  .rail-note { font-size: 10px; }
  .section { padding: 68px 0; }
  .section h2 { font-size: clamp(38px, 10vw, 50px); }
  html[lang="zh-CN"] .section h2 { font-size: clamp(34px, 9vw, 46px); }
  .dark-copy h2 { font-size: clamp(36px, 9.6vw, 48px); }
  .dark-list li { flex-direction: column; gap: 3px; }
  .dark-list-value { text-align: left; }
  .dark-quote { font-size: 22px; }
  .product-facts div { gap: 16px; }
  .product-facts dd { font-size: 12.5px; }
  .spec-group dl div { flex-direction: column; gap: 3px; }
  .spec-group dd { text-align: left; }
  .spec-group dt { max-width: none; }
  .contact-copy h2 { font-size: clamp(38px, 10.4vw, 52px); }
  .contact-email { font-size: clamp(22px, 7vw, 30px); }
  .commercial-lede { font-size: 14px; }
  .footer-bottom { font-size: 9.5px; }
}

@media (max-width: 430px) {
  .rail-item { padding: 14px 15px 16px; }
  .rail-value { font-size: 19px; }
  .rail-label { font-size: 9px; }
  .rail-note { font-size: 9.5px; }
  .hero-actions { width: 100%; }
  .hero-actions .btn { width: 100%; }
  .hero-actions .link-arrow { margin-top: 2px; }
  .contact-meta { gap: 20px; }
  .tag-list { gap: 8px; }
}