:root {
  color-scheme: light;
  --ink: #14221f;
  --muted: #5f706b;
  --line: #dce7e3;
  --surface: #ffffff;
  --canvas: #f5f8f7;
  --brand: #287f70;
  --brand-dark: #175d53;
  --brand-soft: #e7f2ef;
  --accent: #ef933f;
  --notice: #fff7ec;
  --notice-line: #f2d1a7;
  --shadow: 0 18px 50px rgba(20, 34, 31, 0.08);
  --radius: 22px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  background: var(--canvas);
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 0%, rgba(40, 127, 112, 0.09), transparent 28rem),
    radial-gradient(circle at 96% 12%, rgba(239, 147, 63, 0.08), transparent 22rem),
    var(--canvas);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand-dark); text-underline-offset: 0.2em; }
a:hover { color: var(--brand); }

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 100;
  padding: 0.7rem 1rem;
  color: #fff;
  background: var(--brand-dark);
  border-radius: 999px;
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(220, 231, 227, 0.9);
  background: rgba(245, 248, 247, 0.88);
  backdrop-filter: blur(18px);
}

.header-inner,
.page-shell,
.site-footer-inner {
  width: min(1160px, calc(100% - 2rem));
  margin-inline: auto;
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 760;
  letter-spacing: -0.01em;
}

.brand img {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  box-shadow: 0 5px 18px rgba(40, 127, 112, 0.2);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

.header-link,
.language-button {
  min-height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 0.85rem;
  border-radius: 999px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 0.92rem;
  text-decoration: none;
  cursor: pointer;
}

.header-link:hover,
.language-button:hover,
.language-button[aria-pressed="true"] {
  border-color: var(--line);
  color: var(--brand-dark);
  background: var(--surface);
}

button:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(239, 147, 63, 0.55);
  outline-offset: 3px;
}

.page-shell { padding-block: 3.5rem 5rem; }

.page-intro {
  max-width: 820px;
  margin-bottom: 2.6rem;
}

.eyebrow {
  margin: 0 0 0.8rem;
  color: var(--brand-dark);
  font-weight: 720;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin-top: 0;
  color: var(--ink);
  line-height: 1.24;
  letter-spacing: -0.025em;
}

h1 { margin-bottom: 1rem; font-size: clamp(2.2rem, 5vw, 4.5rem); }
h2 { margin-bottom: 0.8rem; font-size: clamp(1.45rem, 2.5vw, 2rem); }
h3 { margin-bottom: 0.45rem; font-size: 1.08rem; }

.intro-copy {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-top: 1.25rem;
}

.meta-chip {
  padding: 0.42rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,0.72);
  color: var(--muted);
  font-size: 0.88rem;
}

.language-panel { display: block; }
.lang-ready .language-panel[hidden] { display: none !important; }

.content-layout {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: 2rem;
  align-items: start;
}

.toc {
  position: sticky;
  top: 96px;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255,255,255,0.78);
  box-shadow: var(--shadow);
}

.toc strong { display: block; margin-bottom: 0.7rem; font-size: 0.92rem; }
.toc a {
  display: block;
  padding: 0.38rem 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-decoration: none;
}
.toc a:hover { color: var(--brand-dark); }

.article-card {
  min-width: 0;
  padding: clamp(1.35rem, 3.5vw, 3.4rem);
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 4px);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.article-card section {
  scroll-margin-top: 105px;
  padding-block: 1.35rem;
  border-bottom: 1px solid var(--line);
}

.article-card section:first-child { padding-top: 0; }
.article-card section:last-child { padding-bottom: 0; border-bottom: 0; }
.article-card p { margin: 0.55rem 0 0; }
.article-card ul,
.article-card ol { margin: 0.7rem 0 0; padding-left: 1.35rem; }
.article-card li + li { margin-top: 0.45rem; }

.notice {
  margin: 1rem 0;
  padding: 1rem 1.1rem;
  border: 1px solid var(--notice-line);
  border-radius: 16px;
  background: var(--notice);
}

.data-grid,
.support-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.data-card,
.support-card {
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #fbfdfc;
}

.data-card p,
.support-card p { color: var(--muted); font-size: 0.95rem; }

.table-wrap {
  margin-top: 1rem;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 16px;
}

table { width: 100%; border-collapse: collapse; min-width: 640px; }
th,
td { padding: 0.85rem 0.9rem; text-align: left; vertical-align: top; border-bottom: 1px solid var(--line); }
th { background: var(--brand-soft); color: var(--brand-dark); font-size: 0.9rem; }
tr:last-child td { border-bottom: 0; }

.contact-box {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  align-items: center;
  margin-top: 1.2rem;
  padding: 1.2rem;
  border-radius: 20px;
  background: var(--brand-soft);
}

.contact-box p { margin: 0.2rem 0 0; color: var(--muted); }

.primary-button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1.1rem;
  border-radius: 14px;
  color: #fff;
  background: var(--brand-dark);
  font-weight: 720;
  text-decoration: none;
  white-space: nowrap;
}

.primary-button:hover { color: #fff; background: var(--brand); }

.site-footer {
  border-top: 1px solid var(--line);
  background: #edf3f1;
}

.site-footer-inner {
  min-height: 116px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.footer-links { display: flex; flex-wrap: wrap; gap: 1rem; }

@media (max-width: 860px) {
  .content-layout { grid-template-columns: 1fr; }
  .toc { position: static; }
  .toc nav { columns: 2; }
}

@media (max-width: 640px) {
  .header-inner { align-items: flex-start; padding-block: 0.75rem; }
  .header-actions { flex-wrap: wrap; justify-content: flex-end; }
  .header-link { display: none; }
  .page-shell { padding-block: 2.4rem 3.5rem; }
  .data-grid,
  .support-grid { grid-template-columns: 1fr; }
  .contact-box { grid-template-columns: 1fr; }
  .primary-button { width: 100%; }
  .site-footer-inner { align-items: flex-start; flex-direction: column; justify-content: center; padding-block: 1.5rem; }
  .toc nav { columns: 1; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}

@media print {
  .site-header,
  .toc,
  .site-footer,
  .skip-link { display: none !important; }
  body { background: #fff; color: #000; }
  .page-shell { width: 100%; padding: 0; }
  .article-card { padding: 0; border: 0; box-shadow: none; }
  .language-panel[hidden] { display: none !important; }
}