:root {
  --bg: #f5f9fc;
  --surface: #ffffff;
  --text: #1a2b3c;
  --muted: #5a6b7c;
  --accent: #2b7cb8;
  --border: #dce8f0;
  --max: 720px;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 15px;
}
.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 24px 20px 48px;
}
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 20px;
  position: sticky;
  top: 0;
  z-index: 10;
}
header .inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 14px; color: var(--accent); }
.lang a {
  color: var(--accent);
  text-decoration: none;
  font-size: 13px;
  margin-left: 12px;
}
.lang a.active { font-weight: 700; text-decoration: underline; }
article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 24px;
  margin-top: 20px;
}
h1 { font-size: 1.5rem; margin: 0 0 8px; line-height: 1.3; }
.meta { color: var(--muted); font-size: 13px; margin-bottom: 20px; }
.note {
  background: #eef6fb;
  border-left: 3px solid var(--accent);
  padding: 10px 14px;
  font-size: 14px;
  margin-bottom: 24px;
  border-radius: 0 8px 8px 0;
}
h2 { font-size: 1.1rem; margin: 28px 0 12px; border-top: 1px solid var(--border); padding-top: 20px; }
h2:first-of-type { border-top: none; padding-top: 0; margin-top: 0; }
h3 { font-size: 1rem; margin: 18px 0 8px; }
p, li { margin: 0 0 10px; }
ul { padding-left: 1.25rem; margin: 0 0 12px; }
table { width: 100%; border-collapse: collapse; font-size: 14px; margin: 12px 0; }
th, td { border: 1px solid var(--border); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: #f0f6fa; }
footer { text-align: center; color: var(--muted); font-size: 12px; margin-top: 24px; }
strong { font-weight: 600; }