:root {
  color-scheme: light dark;
  --page: #f7f8fa;
  --surface: #ffffff;
  --surface-soft: #eef2f6;
  --text: #171a1f;
  --text-secondary: #505966;
  --text-muted: #737d89;
  --line: #dce2e8;
  --accent: #1f67b1;
  --accent-soft: #e8f2fc;
  --focus: #0f5fae;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #111418;
    --surface: #191d22;
    --surface-soft: #222831;
    --text: #f0f3f6;
    --text-secondary: #c3cad2;
    --text-muted: #99a4b0;
    --line: #343b44;
    --accent: #83baf0;
    --accent-soft: #1c344c;
    --focus: #a9d2f8;
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--page);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-underline-offset: 3px;
}

a:hover {
  text-decoration-thickness: 2px;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--page) 92%, transparent);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
}

.nav {
  width: min(100% - 40px, 920px);
  min-height: 64px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
}

.brand img {
  width: 30px;
  height: 30px;
  border-radius: 7px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 18px;
  white-space: nowrap;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  text-decoration: none;
}

.nav-links a[aria-current="page"] {
  color: var(--text);
  font-weight: 650;
}

.page {
  width: min(100% - 40px, 920px);
  margin: 0 auto;
  padding: 64px 0 96px;
}

.page-header {
  max-width: 720px;
  padding-bottom: 36px;
}

.page-header h1 {
  margin: 0;
  font-size: clamp(34px, 6vw, 52px);
  line-height: 1.14;
  letter-spacing: 0;
}

.summary {
  margin: 18px 0 0;
  color: var(--text-secondary);
  font-size: 17px;
}

.meta {
  margin: 14px 0 0;
  color: var(--text-muted);
  font-size: 13px;
}

.language-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.language-nav a {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.document,
.support-block {
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.document h2,
.support-block h2 {
  margin: 38px 0 10px;
  font-size: 22px;
  line-height: 1.35;
  letter-spacing: 0;
}

.document h3,
.support-block h3 {
  margin: 26px 0 6px;
  font-size: 17px;
  line-height: 1.4;
}

.document p,
.document li,
.support-block p,
.support-block li {
  color: var(--text-secondary);
  font-size: 15px;
}

.document ul,
.document ol,
.support-block ul,
.support-block ol {
  padding-left: 22px;
}

.document li + li,
.support-block li + li {
  margin-top: 8px;
}

.english {
  margin-top: 84px;
  padding-top: 52px;
  border-top: 2px solid var(--line);
}

.english > h2:first-child {
  margin-top: 0;
  font-size: 30px;
}

.contact-panel {
  margin-top: 28px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.contact-panel h2,
.contact-panel h3,
.contact-panel p {
  margin-top: 0;
}

.contact-panel p:last-child {
  margin-bottom: 0;
}

.contact-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  margin-top: 8px;
  padding: 10px 16px;
  border-radius: 8px;
  background: var(--accent);
  color: var(--page);
  font-weight: 700;
  text-decoration: none;
}

.note {
  margin: 22px 0;
  padding: 16px 18px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  color: var(--text-secondary);
}

.faq {
  margin-top: 30px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.faq section {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.faq h2,
.faq h3 {
  margin: 0 0 8px;
  font-size: 17px;
}

.faq p {
  margin: 0;
}

.site-footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  width: min(100% - 40px, 920px);
  margin: 0 auto;
  padding: 26px 0 38px;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  color: var(--text-muted);
  font-size: 13px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

@media (max-width: 720px) {
  .nav {
    align-items: flex-start;
    padding: 15px 0;
  }

  .nav-links {
    max-width: 70%;
    justify-content: flex-end;
    flex-wrap: wrap;
    gap: 8px 14px;
  }

  .page {
    padding-top: 44px;
  }

  .faq {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    flex-direction: column;
  }
}

@media (max-width: 460px) {
  .nav-links a:not([aria-current="page"]) {
    display: none;
  }

  .page,
  .nav,
  .footer-inner {
    width: min(100% - 32px, 920px);
  }

  .page-header h1 {
    font-size: 34px;
  }

  .document p,
  .document li,
  .support-block p,
  .support-block li {
    font-size: 14px;
  }
}

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

@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
  .site-header {
    background: var(--page);
  }
}