:root {
  color-scheme: light dark;
  --page: #f2f4f1;
  --surface: #f8f9f6;
  --surface-strong: #ffffff;
  --ink: #101921;
  --copy: #303b42;
  --muted: #667178;
  --soft: #8c969b;
  --line: color-mix(in srgb, var(--ink) 14%, transparent);
  --line-strong: color-mix(in srgb, var(--ink) 27%, transparent);
  --accent: #00788a;
  --accent-strong: #006776;
  --accent-soft: #d9f3f4;
  --action-ink: #ffffff;
  --focus: #00788a;
  --max-width: 1360px;
  --reading-width: 760px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --font-ui: Inter, "Avenir Next", Avenir, "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-display: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", "Songti SC", STSong, "Noto Serif CJK SC", Georgia, serif;
  font-family: var(--font-ui);
  background: var(--page);
  color: var(--ink);
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #0b1419;
    --surface: #101b21;
    --surface-strong: #152229;
    --ink: #eef6f2;
    --copy: #cbd7d3;
    --muted: #98a8a6;
    --soft: #70807f;
    --accent: #35cfe2;
    --accent-strong: #72deea;
    --accent-soft: #12353d;
    --action-ink: #061216;
    --focus: #4bd5e7;
  }
}

html[data-theme="light"] {
  color-scheme: light;
  --page: #f2f4f1;
  --surface: #f8f9f6;
  --surface-strong: #ffffff;
  --ink: #101921;
  --copy: #303b42;
  --muted: #667178;
  --soft: #8c969b;
  --accent: #00788a;
  --accent-strong: #006776;
  --accent-soft: #d9f3f4;
  --action-ink: #ffffff;
  --focus: #00788a;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --page: #0b1419;
  --surface: #101b21;
  --surface-strong: #152229;
  --ink: #eef6f2;
  --copy: #cbd7d3;
  --muted: #98a8a6;
  --soft: #70807f;
  --accent: #35cfe2;
  --accent-strong: #72deea;
  --accent-soft: #12353d;
  --action-ink: #061216;
  --focus: #4bd5e7;
}

@media (prefers-color-scheme: light) {
  html[data-theme="auto"] .theme-dark-only { display: none !important; }
}

@media (prefers-color-scheme: dark) {
  html[data-theme="auto"] .theme-light-only { display: none !important; }
}

html[data-theme="light"] .theme-dark-only,
html[data-theme="dark"] .theme-light-only {
  display: none !important;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 110px;
  background: var(--page);
}

body {
  min-width: 320px;
  margin: 0;
  background: var(--page);
  color: var(--copy);
  font-family: var(--font-ui);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button, select { font: inherit; }
a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 0.24em; }
img { display: block; max-width: 100%; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { color: var(--ink); }

.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  padding: 10px 14px;
  background: var(--ink);
  color: var(--page);
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

.skip-link:focus { transform: translateY(0); }

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--page) 94%, transparent);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
}

.header-inner {
  width: min(calc(100% - 48px), var(--max-width));
  min-height: 78px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(128px, 1fr) auto minmax(265px, 1fr);
  align-items: center;
  gap: 28px;
}

.brand {
  width: 112px;
  display: block;
  line-height: 0;
}

.brand-lockup { width: 112px; height: auto; }

.primary-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(22px, 3vw, 44px);
}

.primary-nav a,
.footer-links a,
.route-links a {
  position: relative;
  color: var(--copy);
  font-size: 0.86rem;
  font-weight: 620;
  text-decoration: none;
}

.primary-nav a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -8px;
  left: 0;
  height: 1px;
  background: var(--accent);
  opacity: 0;
  transform: scaleX(0.35);
  transition: opacity 160ms ease, transform 160ms ease;
}

.primary-nav a:hover::after,
.primary-nav a:focus-visible::after,
.primary-nav a[aria-current="page"]::after {
  opacity: 1;
  transform: scaleX(1);
}

.site-controls {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
}

.language-control select,
.theme-switch {
  min-height: 36px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface-strong);
  color: var(--copy);
}

.language-control select {
  min-width: 92px;
  padding: 0 28px 0 10px;
  cursor: pointer;
  font-size: 0.73rem;
  font-weight: 640;
}

.theme-switch {
  display: inline-flex;
  align-items: center;
  padding: 3px;
}

.theme-switch button {
  min-width: 46px;
  min-height: 28px;
  padding: 0 8px;
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.68rem;
  font-weight: 680;
}

.theme-switch button:hover { color: var(--ink); }
.theme-switch button[aria-pressed="true"] { background: var(--accent-soft); color: var(--ink); }

.hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  width: min(calc(100% - 48px), var(--max-width));
  min-height: clamp(560px, calc(65svh - 78px), 640px);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
  align-items: center;
  gap: clamp(36px, 7vw, 108px);
  border-bottom: 1px solid var(--line);
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 690px;
  padding: 76px 0 92px clamp(0px, 4vw, 58px);
}

.eyebrow,
.section-index {
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 740;
  letter-spacing: 0.14em;
  line-height: 1.4;
  text-transform: uppercase;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 26px;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--accent);
}

.hero h1,
.document-hero h1 {
  max-width: 820px;
  margin-bottom: 26px;
  font-family: var(--font-display);
  font-size: clamp(4rem, 6.4vw, 7rem);
  font-weight: 520;
  letter-spacing: -0.054em;
  line-height: 0.93;
  text-wrap: balance;
}

.hero-lead {
  max-width: 570px;
  margin-bottom: 34px;
  color: var(--copy);
  font-size: clamp(1.04rem, 1.4vw, 1.22rem);
  line-height: 1.55;
}

.primary-action {
  min-height: 48px;
  width: fit-content;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 22px;
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: var(--action-ink);
  font-size: 0.88rem;
  font-weight: 720;
  text-decoration: none;
  transition: background-color 160ms ease, border-color 160ms ease, transform 160ms ease;
}

.primary-action:hover { background: var(--accent-strong); border-color: var(--accent-strong); transform: translateY(-1px); }

.text-action {
  width: fit-content;
  display: inline-block;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--accent);
  color: var(--ink);
  font-size: 0.86rem;
  font-weight: 700;
  text-decoration: none;
}

.text-action:hover { color: var(--accent-strong); }

.hero-mark {
  align-self: stretch;
  display: grid;
  place-items: center;
  border-left: 1px solid var(--line);
}

.hero-mark img {
  width: clamp(175px, 23vw, 315px);
  max-height: 68vh;
  opacity: 0.94;
}

.section-rule {
  width: min(calc(100% - 48px), var(--max-width));
  margin: 0 auto;
  padding: clamp(86px, 10vw, 146px) 0;
  border-bottom: 1px solid var(--line);
}

.work-section {
  padding-top: clamp(70px, 7vw, 96px);
  display: grid;
  grid-template-columns: minmax(270px, 0.38fr) minmax(0, 0.62fr);
  align-items: center;
  gap: clamp(48px, 7vw, 100px);
}

.section-intro h2,
.section-heading h2,
.company-section h2,
.support-callout h2,
.support-route h2,
.document-content h2 {
  font-family: var(--font-display);
  font-weight: 540;
  letter-spacing: -0.035em;
}

.section-intro h2,
.section-heading h2,
.company-section h2 {
  margin-bottom: 24px;
  font-size: clamp(2.4rem, 4vw, 4.7rem);
  line-height: 1;
  text-wrap: balance;
}

.section-intro > p:not(.section-index),
.company-copy p {
  max-width: 630px;
  color: var(--copy);
  font-size: 1.03rem;
}

.availability {
  margin: 28px 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  color: var(--muted) !important;
  font-size: 0.86rem !important;
}

.product-proof {
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-md);
  background: var(--surface-strong);
  color: var(--ink);
  text-decoration: none;
  transition: border-color 160ms ease, transform 160ms ease;
}

.product-proof:hover { border-color: var(--accent); transform: translateY(-2px); }
.product-proof img { width: 100%; height: auto; background: #f4f0f5; }

.proof-caption {
  min-height: 54px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 18px;
  border-top: 1px solid var(--line);
  font-size: 0.76rem;
  font-weight: 680;
}

.section-heading { max-width: 920px; margin-bottom: 68px; }

.principles {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line-strong);
}

.principles article {
  min-height: 280px;
  padding: 30px clamp(22px, 3vw, 42px) 34px 0;
  border-right: 1px solid var(--line);
}

.principles article:not(:first-child) { padding-left: clamp(22px, 3vw, 42px); }
.principles article:last-child { padding-right: 0; border-right: 0; }
.principle-number { margin-bottom: 56px; color: var(--accent); font-family: var(--font-display); font-size: 1.15rem; }
.principles h3 { margin-bottom: 18px; font-size: 1.15rem; line-height: 1.35; }
.principles article > p:last-child { margin: 0; color: var(--muted); font-size: 0.93rem; }

.company-section {
  display: grid;
  grid-template-columns: minmax(0, 0.48fr) minmax(0, 0.52fr);
  gap: clamp(48px, 8vw, 120px);
}

.company-copy p { margin-bottom: 24px; }
.company-copy .text-action { margin-top: 10px; }

.support-callout {
  width: min(calc(100% - 48px), var(--max-width));
  margin: 0 auto;
  padding: clamp(68px, 8vw, 104px) 0;
  display: grid;
  grid-template-columns: 0.28fr 1fr auto;
  align-items: center;
  gap: 36px;
}

.support-callout .section-index { margin: 0; }
.support-callout h2 { margin: 0 0 10px; font-size: clamp(2rem, 3.2vw, 3.3rem); line-height: 1.05; }
.support-callout div p { max-width: 650px; margin: 0; color: var(--muted); }

.site-footer {
  width: min(calc(100% - 48px), var(--max-width));
  min-height: 180px;
  margin: 0 auto;
  padding: 38px 0;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: start;
  gap: 28px;
  border-top: 1px solid var(--line-strong);
}

.footer-brand { display: flex; align-items: center; gap: 12px; }
.footer-brand img { width: 16px; height: 30px; }
.footer-brand p { margin: 0; color: var(--muted); font-size: 0.82rem; }
.footer-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 14px 28px; }
.footer-links a:hover, .footer-links a[aria-current="page"] { color: var(--accent); }
.copyright { grid-column: 1 / -1; margin: auto 0 0; color: var(--soft); font-size: 0.75rem; }

.document-shell {
  width: min(calc(100% - 48px), var(--max-width));
  margin: 0 auto;
}

.document-hero {
  max-width: 1060px;
  padding: clamp(84px, 10vw, 142px) 0 clamp(76px, 9vw, 124px);
}

.document-hero h1 { font-size: clamp(3.6rem, 6.6vw, 6.9rem); }
.document-hero > p:not(.eyebrow, .effective-date) { max-width: 780px; color: var(--copy); font-size: clamp(1.05rem, 1.5vw, 1.25rem); }
.document-hero--compact { padding-bottom: 78px; }
.document-actions { margin-top: 34px; display: flex; align-items: center; gap: 26px; }
.effective-date { margin-top: 30px; color: var(--muted); font-size: 0.8rem; }

.support-route {
  padding: clamp(34px, 5vw, 64px);
  display: grid;
  grid-template-columns: minmax(190px, 0.3fr) minmax(0, 0.7fr);
  gap: 42px;
  border: 1px solid var(--line-strong);
  background: var(--surface);
}

.support-route h2 { margin: 0; font-size: clamp(2.5rem, 4vw, 4.4rem); }
.support-route p { max-width: 720px; }
.route-links { display: flex; flex-wrap: wrap; gap: 14px 26px; margin-top: 24px; }
.route-links a { color: var(--accent-strong); text-decoration: underline; }

.document-grid {
  padding: clamp(82px, 10vw, 138px) 0;
  display: grid;
  grid-template-columns: minmax(180px, 0.25fr) minmax(0, 0.75fr);
  align-items: start;
  gap: clamp(48px, 9vw, 130px);
  border-bottom: 1px solid var(--line);
}

.document-toc {
  position: sticky;
  top: 112px;
  display: grid;
  gap: 14px;
}

.document-toc p { margin-bottom: 8px; color: var(--muted); font-size: 0.7rem; font-weight: 760; letter-spacing: 0.12em; text-transform: uppercase; }
.document-toc a { color: var(--muted); font-size: 0.82rem; text-decoration: none; }
.document-toc a:hover { color: var(--accent-strong); }

.document-content { max-width: var(--reading-width); }
.document-content section { padding-bottom: 68px; margin-bottom: 68px; border-bottom: 1px solid var(--line); }
.document-content section:last-child { padding-bottom: 0; margin-bottom: 0; border-bottom: 0; }
.document-content h2 { margin-bottom: 26px; font-size: clamp(2rem, 3.4vw, 3.2rem); line-height: 1.08; }
.document-content p, .document-content li { color: var(--copy); font-size: 1rem; line-height: 1.78; }
.document-content a { color: var(--accent-strong); }
.document-content ul, .document-content ol { padding-left: 1.35em; }
.document-content li + li { margin-top: 12px; }

html[lang^="zh"] .eyebrow,
html[lang^="zh"] .section-index,
html[lang^="zh"] .document-toc p {
  letter-spacing: 0.08em;
  text-transform: none;
}

html[lang^="zh"] .hero h1,
html[lang^="zh"] .document-hero h1,
html[lang^="zh"] .section-intro h2,
html[lang^="zh"] .section-heading h2,
html[lang^="zh"] .company-section h2 {
  letter-spacing: -0.035em;
  line-height: 1.06;
}

@media (max-width: 1100px) {
  .header-inner { grid-template-columns: auto 1fr; padding: 14px 0; }
  .primary-nav { grid-column: 1 / -1; grid-row: 2; justify-content: flex-start; }
  .site-controls { grid-column: 2; grid-row: 1; }
  .hero { min-height: 660px; grid-template-columns: minmax(0, 1.12fr) minmax(220px, 0.88fr); }
  .support-callout { grid-template-columns: 1fr auto; }
  .support-callout .section-index { grid-column: 1 / -1; }
}

@media (max-width: 820px) {
  html { scroll-padding-top: 150px; }
  .header-inner { width: min(calc(100% - 32px), var(--max-width)); gap: 14px; }
  .primary-nav { width: 100%; overflow-x: auto; justify-content: space-between; gap: 22px; padding: 5px 0 2px; scrollbar-width: none; }
  .primary-nav::-webkit-scrollbar { display: none; }
  .site-controls { gap: 6px; }
  .language-control select { min-width: 78px; }
  .theme-switch button { min-width: 39px; padding: 0 5px; }
  .hero, .section-rule, .support-callout, .site-footer, .document-shell { width: min(calc(100% - 32px), var(--max-width)); }
  .hero { min-height: auto; grid-template-columns: 1fr; }
  .hero-copy { max-width: 700px; padding: 80px 0 0; }
  .hero h1 { font-size: clamp(3.7rem, 14vw, 6.3rem); }
  .hero-mark { min-height: 380px; border-top: 1px solid var(--line); border-left: 0; }
  .hero-mark img { width: 160px; max-height: 320px; }
  .work-section, .company-section { grid-template-columns: 1fr; }
  .product-proof { order: -1; }
  .principles { grid-template-columns: 1fr; }
  .principles article, .principles article:not(:first-child) { min-height: auto; padding: 30px 0; border-right: 0; border-bottom: 1px solid var(--line); }
  .principles article:last-child { border-bottom: 0; }
  .principle-number { margin-bottom: 24px; }
  .support-callout { grid-template-columns: 1fr; }
  .support-callout .section-index { grid-column: auto; }
  .site-footer { grid-template-columns: 1fr; }
  .footer-links { justify-content: flex-start; }
  .copyright { grid-column: auto; }
  .support-route, .document-grid { grid-template-columns: 1fr; }
  .document-toc { position: static; padding-bottom: 34px; border-bottom: 1px solid var(--line); }
}

@media (max-width: 560px) {
  body { font-size: 15px; }
  .header-inner { grid-template-columns: auto 1fr; }
  .brand, .brand-lockup { width: 88px; }
  .language-control select { width: 92px; min-width: 92px; padding-right: 20px; }
  .theme-switch button { min-width: 34px; font-size: 0.63rem; }
  .hero-copy { padding-top: 64px; }
  .hero h1, .document-hero h1 { font-size: clamp(3.2rem, 15vw, 4.8rem); }
  .hero-mark { min-height: 300px; }
  .hero-mark img { width: 130px; max-height: 260px; }
  .section-rule { padding: 76px 0; }
  .section-intro h2, .section-heading h2, .company-section h2 { font-size: clamp(2.45rem, 12vw, 3.8rem); }
  .section-heading { margin-bottom: 42px; }
  .product-proof img { min-height: 190px; object-fit: cover; object-position: left center; }
  .support-callout { padding: 68px 0; }
  .document-hero { padding: 70px 0; }
  .document-actions { align-items: flex-start; flex-direction: column; gap: 20px; }
  .support-route { padding: 28px 24px; }
  .document-grid { padding: 72px 0; gap: 46px; }
  .document-content section { padding-bottom: 50px; margin-bottom: 50px; }
}

@media (max-width: 360px) {
  .header-inner { grid-template-columns: 1fr; }
  .site-controls { grid-column: 1; grid-row: 2; justify-content: flex-start; }
  .primary-nav { grid-row: 3; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; }
}