:root {
  --bg: #f7f8fa;
  --card: #fff;
  --fg: #1f2328;
  --muted: #656d76;
  --accent: #2563eb;
  --border: #e5e7eb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --card: #171a21;
    --fg: #e6e8eb;
    --muted: #9aa3ad;
    --accent: #6ea0ff;
    --border: #2a2f3a;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.7 -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}
main { max-width: 760px; margin: 0 auto; padding: 40px 20px 60px; }
header.hero { text-align: center; padding: 24px 0 8px; }
header.hero img { width: 96px; height: 96px; border-radius: 22px; }
h1 { margin: 12px 0 4px; font-size: 32px; }
h2 { margin-top: 36px; font-size: 22px; }
.tag { color: var(--muted); margin: 0; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 8px 24px 20px;
  margin-top: 20px;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { padding-left: 1.2em; }
nav { text-align: center; margin-top: 12px; font-size: 14px; }
nav a { margin: 0 8px; }
.meta { color: var(--muted); font-size: 14px; }
footer { text-align: center; color: var(--muted); font-size: 13px; margin-top: 40px; }
.lang-switch { text-align: right; font-size: 14px; }
.lang-switch a { margin-left: 12px; }