:root {
  --bg: #f4f7f9;
  --card: #ffffff;
  --text: #1f2a37;
  --sub: #536171;
  --accent: #4a90e2;
  --line: #e7edf3;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, #f7fbff 0%, var(--bg) 100%);
}
.wrap {
  max-width: 920px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}
.top {
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 10;
}
.top .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
}
.brand {
  font-weight: 700;
  letter-spacing: .2px;
}
.brand a { color: inherit; text-decoration: none; }
.lang-badge {
  font-size: 12px;
  color: var(--sub);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 10px;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
  margin-top: 14px;
}
h1 {
  font-size: 28px;
  margin: 8px 0 6px;
}
.subtitle {
  color: var(--sub);
  margin: 0 0 8px;
}
h2 {
  margin: 20px 0 10px;
  font-size: 20px;
}
h3 {
  margin: 16px 0 8px;
  font-size: 16px;
}
p, li {
  line-height: 1.72;
  font-size: 15px;
  color: var(--text);
}
ul { margin: 8px 0 10px 20px; }
hr {
  border: 0;
  border-top: 1px dashed var(--line);
  margin: 18px 0;
}
.note {
  font-size: 13px;
  color: var(--sub);
  background: #f4f9ff;
  border: 1px solid #dcecff;
  border-radius: 10px;
  padding: 10px 12px;
}
.pill {
  display: inline-block;
  background: #edf5ff;
  color: #2f6eb6;
  border-radius: 999px;
  padding: 4px 10px;
  font-size: 12px;
  margin-right: 8px;
}
.footer {
  color: var(--sub);
  font-size: 12px;
  margin-top: 20px;
}
.anchor-list a {
  color: var(--accent);
  text-decoration: none;
  margin-right: 12px;
}
.anchor-list a:hover { text-decoration: underline; }