:root {
    --bg: #f7f8fa;
    --surface: #ffffff;
    --text: #1d2330;
    --text-muted: #5b6473;
    --brand: #5292D7;
    --border: #e6e8ee;
  }
  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #0f1218;
      --surface: #161b22;
      --text: #e8ecf2;
      --text-muted: #9aa3b2;
      --border: #232a35;
    }
  }
  * { box-sizing: border-box; }
  html, body { margin: 0; padding: 0; }
  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Noto Sans TC', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
  }
  main {
    max-width: 720px;
    margin: 0 auto;
    padding: 48px 22px 80px;
  }
  .back-link {
    display: inline-block;
    color: var(--brand);
    text-decoration: none;
    font-size: 14px;
    margin-bottom: 24px;
  }
  .back-link:hover { text-decoration: underline; }
  h1 {
    font-size: 28px;
    font-weight: 700;
    margin: 0 0 6px;
    letter-spacing: 0.5px;
  }
  .updated { color: var(--text-muted); font-size: 13px; margin: 0 0 32px; }
  h2 {
    font-size: 18px;
    font-weight: 700;
    margin: 32px 0 10px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
  }
  h2:first-of-type { border-top: none; padding-top: 0; }
  p, li { color: var(--text); font-size: 15px; }
  ul { padding-left: 22px; }
  li { margin: 4px 0; }
  a { color: var(--brand); }
  .muted { color: var(--text-muted); font-size: 13px; }
  code {
    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 1px 5px;
    font-size: 13px;
  }