:root {
  --text: #1a1a1a;
  --muted: #555;
  --border: #e5e5e5;
  --accent: #1a73e8;
  --zh-bg: #f8fafc;
  --en-bg: #faf8f5;
}

* { box-sizing: border-box; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
  max-width: 960px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
  color: var(--text);
}

header.site-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}

header.site-header h1 {
  font-size: 1.6rem;
  margin: 0 0 0.35rem;
}

.lang-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  margin-top: 0.75rem;
}

.lang-nav a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
}

.lang-nav a:hover { text-decoration: underline; }

.meta { color: var(--muted); font-size: 0.85rem; margin: 0; }

.doc-links { margin-top: 0.75rem; font-size: 0.9rem; }
.doc-links a { color: var(--accent); margin-right: 1rem; }

section.lang-block {
  margin-top: 2.5rem;
  scroll-margin-top: 1rem;
}

section.lang-block > h2 {
  font-size: 1.15rem;
  margin: 0 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}

.bilingual-grid {
  display: grid;
  gap: 1rem;
}

@media (min-width: 768px) {
  .bilingual-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
  }
}

.lang-card {
  padding: 1rem 1.1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
}

.lang-card.zh { background: var(--zh-bg); }
.lang-card.en { background: var(--en-bg); }

.lang-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.lang-card h3 {
  font-size: 1rem;
  margin: 0 0 0.75rem;
}

.lang-card p,
.lang-card li {
  font-size: 0.92rem;
  margin: 0.4rem 0;
}

.lang-card ul {
  margin: 0.5rem 0 0;
  padding-left: 1.25rem;
}

a { color: var(--accent); }
code { font-size: 0.88em; background: #eee; padding: 0.1em 0.35em; border-radius: 4px; }

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--muted);
}