:root {
  --bg: #ffffff;
  --text: #1f2a2b;
  --muted: #5b6b6c;
  --accent: #1a8a8f;
  --border: #dde7e8;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #102728;
    --text: #e6f1f2;
    --muted: #9fb3b4;
    --accent: #5cc8cd;
    --border: #24403f;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.75 -apple-system, BlinkMacSystemFont, "PingFang TC", "Noto Sans TC", sans-serif;
}
main { max-width: 680px; margin: 0 auto; padding: 32px 16px 64px; }
h1 { font-size: 26px; line-height: 1.4; margin: 0 0 4px; }
h2 { font-size: 19px; margin: 32px 0 8px; }
p, li { margin: 0 0 8px; }
ul { padding-left: 20px; }
a { color: var(--accent); }
.meta { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
nav { border-top: 1px solid var(--border); margin-top: 40px; padding-top: 16px; font-size: 14px; }
nav a { margin-right: 16px; }