:root {
  color-scheme: light;
  --ink: #1b1b1f;
  --muted: #5f6368;
  --line: #d7dde6;
  --paper: #fffdf8;
  --wash: #f3f0e8;
  --accent: #0f766e;
  --accent-soft: #d7f2ed;
}

* {
  box-sizing: border-box;
}

html[data-lang="zh"] .lang-en,
html[data-lang="en"] .lang-zh {
  display: none !important;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", "Segoe UI", sans-serif;
  line-height: 1.75;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(15, 118, 110, 0.08) 1px, transparent 1px),
    linear-gradient(rgba(15, 118, 110, 0.06) 1px, transparent 1px),
    var(--wash);
  background-size: 36px 36px;
}

main {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 38px 0 72px;
}

.document,
article {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  box-shadow: 0 24px 80px rgba(31, 41, 55, 0.12);
  overflow: hidden;
}

article {
  padding: clamp(24px, 6vw, 58px);
}

.hero {
  padding: 42px clamp(24px, 6vw, 56px) 34px;
  border-bottom: 1px solid var(--line);
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
}

.back {
  color: var(--accent);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.language-switch {
  display: inline-flex;
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #ffffff;
}

.language-switch button {
  min-width: 44px;
  min-height: 32px;
  padding: 5px 12px;
  border: 0;
  border-radius: 999px;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
}

html[data-lang="zh"] [data-lang-toggle="zh"],
html[data-lang="en"] [data-lang-toggle="en"] {
  color: #ffffff;
  background: var(--accent);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
}

h1,
h2 {
  font-family: "Noto Serif SC", "Songti SC", Georgia, serif;
  line-height: 1.25;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(30px, 5vw, 48px);
}

h2 {
  margin: 34px 0 10px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 22px;
}

p,
li {
  color: #30343b;
  font-size: 16px;
}

.lead,
.summary {
  max-width: 740px;
  color: var(--muted);
  font-size: 17px;
}

.meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border-bottom: 1px solid var(--line);
}

article .meta {
  gap: 10px 22px;
  margin: 26px 0 30px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
}

.meta div {
  padding: 16px clamp(20px, 5vw, 36px);
  background: rgba(255, 253, 248, 0.92);
}

article .meta div {
  padding: 0;
  background: transparent;
}

.meta span {
  display: block;
  color: var(--muted);
  font-size: 13px;
}

.meta strong {
  display: block;
  margin-top: 3px;
  font-size: 16px;
}

.doc-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  padding: clamp(24px, 5vw, 40px);
}

.doc-card {
  display: block;
  min-height: 154px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: inherit;
  text-decoration: none;
  background: #ffffff;
  transition: border-color 180ms ease, transform 180ms ease, box-shadow 180ms ease;
}

.doc-card:hover,
.doc-card:focus-visible {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 14px 34px rgba(15, 118, 110, 0.13);
  outline: none;
}

.doc-card strong {
  display: block;
  margin-bottom: 10px;
  color: var(--accent);
  font-size: 21px;
}

.doc-card span {
  display: block;
  color: var(--muted);
  font-size: 15px;
}

.page-footer {
  padding: 0 clamp(24px, 6vw, 56px) 36px;
  color: var(--muted);
  font-size: 14px;
}

table {
  width: 100%;
  margin: 16px 0 6px;
  border-collapse: collapse;
  overflow-wrap: anywhere;
  background: #ffffff;
}

th,
td {
  padding: 12px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--accent-soft);
  color: #123f3a;
}

ul {
  padding-left: 22px;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

@media (max-width: 720px) {
  main {
    width: min(100% - 20px, 920px);
    padding: 20px 0 40px;
  }

  article {
    padding: 22px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column-reverse;
  }

  .meta,
  .doc-nav {
    grid-template-columns: 1fr;
  }

  .doc-card {
    min-height: auto;
  }

  table,
  thead,
  tbody,
  tr,
  th,
  td {
    display: block;
  }

  th {
    display: none;
  }

  td {
    border-top: 0;
  }

  td:first-child {
    border-top: 1px solid var(--line);
    font-weight: 700;
    color: var(--accent);
  }
}