:root {
  color-scheme: light dark;
  --page: #f4f6f9;
  --surface: #ffffff;
  --surface-raised: #eaf0f6;
  --ink: #11151d;
  --muted: #596576;
  --faint: #7c8795;
  --line: #d7e0ea;
  --accent: #28689f;
  --accent-strong: #174c79;
  --on-accent: #ffffff;
  --gold: #96702d;
  --shadow: 0 18px 55px rgba(29, 53, 77, 0.10);
  --content: 1120px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #0e1117;
    --surface: #171c24;
    --surface-raised: #202936;
    --ink: #f3f6fa;
    --muted: #b3becc;
    --faint: #8995a4;
    --line: #2e3947;
    --accent: #72b1df;
    --accent-strong: #9acbef;
    --on-accent: #101820;
    --gold: #d5b36e;
    --shadow: 0 20px 58px rgba(0, 0, 0, 0.30);
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background: var(--page);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang TC", "Noto Sans TC", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-wrap: anywhere;
}

a {
  color: var(--accent);
  font-weight: 650;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover { color: var(--accent-strong); }

a:focus-visible,
button:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent), transparent 45%);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 20;
  padding: 10px 14px;
  color: #fff;
  background: #11151d;
  border-radius: 8px;
  transform: translateY(-180%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  width: 100%;
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
  padding: 10px max(20px, calc((100% - var(--content)) / 2));
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--page), transparent 10%);
  backdrop-filter: blur(18px) saturate(1.2);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 800;
  text-decoration: none;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 8px;
  box-shadow: 0 6px 18px rgba(40, 104, 159, 0.18);
}

.site-header nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 22px;
}

.site-header nav a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--muted);
  font-size: 0.92rem;
  text-decoration: none;
}

.site-header nav .language-link {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: var(--surface);
}

main,
footer {
  width: min(var(--content), calc(100% - 40px));
  margin-inline: auto;
}

.intro {
  max-width: 850px;
  padding: 76px 0 70px;
}

.app-icon {
  width: 96px;
  height: 96px;
  display: block;
  margin-bottom: 30px;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--gold);
  font-size: 0.76rem;
  font-weight: 800;
  line-height: 1.4;
  letter-spacing: 0;
}

h1,
h2,
h3,
p { margin-top: 0; }

h1 {
  margin-bottom: 24px;
  font-size: 3.5rem;
  line-height: 1.12;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 12px;
  font-size: 1.8rem;
  line-height: 1.25;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.16rem;
  line-height: 1.42;
  letter-spacing: 0;
}

p,
li {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.78;
}

.lede {
  max-width: 720px;
  margin-bottom: 26px;
  font-size: 1.16rem;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 0.96rem;
  line-height: 1.25;
  text-decoration: none;
  transition: transform 150ms ease-out, background-color 150ms ease-out, border-color 150ms ease-out;
}

.button:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.button:active { transform: scale(0.98); }

.button.primary {
  color: var(--on-accent);
  border-color: var(--accent-strong);
  background: var(--accent-strong);
}

.button.secondary {
  color: var(--ink);
  background: var(--surface);
}

.facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  padding-bottom: 64px;
}

.facts article {
  min-height: 190px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 12px 36px rgba(29, 53, 77, 0.06);
}

.facts h2 {
  margin-top: 24px;
  font-size: 1.14rem;
}

.facts p {
  margin-bottom: 0;
  font-size: 0.94rem;
  line-height: 1.68;
}

.fact-mark {
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.support-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(310px, 0.62fr);
  gap: 44px;
  align-items: center;
  padding: 36px 0;
  border-block: 1px solid var(--line);
}

.support-band p:last-child { margin-bottom: 0; }

.support-email {
  display: grid;
  gap: 5px;
  min-height: 82px;
  align-content: center;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: var(--surface);
  text-decoration: none;
  overflow-wrap: anywhere;
}

.support-email span {
  color: var(--faint);
  font-size: 0.78rem;
}

.support-email strong { font-size: 0.96rem; }

.operator { margin-top: 18px; }

.support-details {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 48px;
  padding: 36px 0 48px;
}

.support-details ul { padding-left: 1.3rem; }
.support-details li { margin-bottom: 8px; }
.support-note { border-left: 3px solid var(--accent); padding-left: 16px; }
.contact-actions { display: grid; gap: 12px; margin-bottom: 20px; }
.contact-actions .button { justify-content: flex-start; }

.faq { max-width: 800px; padding-bottom: 16px; }
.faq details { padding: 8px 0; border-bottom: 1px solid var(--line); }
.faq summary {
  padding: 12px 0;
  min-height: 44px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 650;
  line-height: 1.5;
}
.faq details p { margin: 4px 0 16px; }
summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.copyright-line { color: var(--ink); font-weight: 650; }

.policy-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 720px);
  justify-content: space-between;
  gap: 72px;
  padding: 92px 0 70px;
}

.policy-layout aside {
  position: sticky;
  top: 104px;
  align-self: start;
}

.updated {
  color: var(--faint);
  font-size: 0.84rem;
}

.toc {
  display: grid;
  gap: 2px;
  margin-top: 24px;
}

.toc a {
  min-height: 44px;
  padding: 9px 10px;
  border-left: 2px solid transparent;
  color: var(--muted);
  font-size: 0.9rem;
  text-decoration: none;
}

.toc a:hover {
  border-left-color: var(--accent);
  color: var(--ink);
  background: var(--surface-raised);
}

.policy-copy > section {
  padding: 0 0 30px;
  margin-bottom: 30px;
  border-bottom: 1px solid var(--line);
}

.policy-copy > section:last-child {
  margin-bottom: 0;
  border-bottom: 0;
}

.policy-copy p:last-child { margin-bottom: 0; }

.source-links {
  display: grid;
  gap: 8px;
  padding-left: 1.2rem;
  margin: 16px 0 0;
}

footer {
  min-height: 92px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px 0;
  border-top: 1px solid var(--line);
}

footer div {
  display: grid;
  gap: 3px;
}

footer { flex-wrap: wrap; }
footer nav { display: flex; flex-wrap: wrap; gap: 18px; }
footer nav a { display: inline-flex; align-items: center; min-height: 44px; }
footer p { line-height: 1.7; }

footer span,
footer p {
  margin: 0;
  color: var(--faint);
  font-size: 0.82rem;
}

@media (max-width: 820px) {
  html { scroll-padding-top: 24px; }
  .site-header { position: static; padding-inline: 16px; }
  .site-header nav { gap: 14px; }

  main,
  footer {
    width: min(100% - 32px, 680px);
  }

  .intro { padding: 52px 0 48px; }
  h1 { font-size: 2.5rem; }

  .facts {
    grid-template-columns: 1fr;
    padding-bottom: 48px;
  }

  .facts article { min-height: auto; }

  .support-band {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 28px 0;
  }

  .support-details { grid-template-columns: 1fr; gap: 20px; }

  .policy-layout {
    grid-template-columns: 1fr;
    gap: 38px;
    padding-top: 64px;
  }

  .policy-layout aside { position: static; }
  .toc { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 520px) {
  .site-header { min-height: 62px; }

  .brand img {
    width: 38px;
    height: 38px;
  }

  .site-header { gap: 4px; }
  .site-header .brand { width: 100%; }
  .site-header nav { gap: 4px 14px; }

  .app-icon {
    width: 80px;
    height: 80px;
    margin-bottom: 24px;
  }

  .intro { padding-top: 40px; }

  h1 {
    font-size: 2.12rem;
    line-height: 1.16;
  }

  h2 { font-size: 1.52rem; }
  .lede { font-size: 1.04rem; }
  .actions { flex-direction: column; }
  .button { width: 100%; }

  .facts article { padding: 22px; }
  .toc { grid-template-columns: 1fr; }

  footer {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media print {
  .site-header, .actions, .contact-actions, .toc, .skip-link, footer nav { display: none; }
  body { color: #000; background: #fff; }
  main, footer { width: 100%; }
  .policy-layout, .support-band, .support-details { display: block; padding: 20px 0; }
  .policy-layout aside { position: static; }
  p, li, .updated { color: #222; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}