:root {
  color-scheme: light;
  --text: #171717;
  --muted: #525252;
  --line: #e5e5e5;
  --bg: #fafafa;
  --card: #ffffff;
  --accent: #171717;
  --link: #2563eb;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
}
a { color: var(--link); }
header, footer { background: var(--card); }
header { border-bottom: 1px solid var(--line); }
footer { border-top: 1px solid var(--line); margin-top: 48px; }
.bar, .wrap, .foot {
  max-width: 880px;
  margin: 0 auto;
  padding: 16px 20px;
}
.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand { color: var(--text); text-decoration: none; font-weight: 700; font-size: 18px; }
nav { display: flex; flex-wrap: wrap; gap: 12px 16px; }
nav a { color: var(--muted); text-decoration: none; font-size: 13px; }
nav a:hover, nav a[aria-current="page"] { color: var(--text); }
main.wrap {
  margin: 28px auto 24px;
  padding: 36px 28px 48px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}
h1 { font-size: 28px; line-height: 1.35; margin: 0 0 12px; }
h2 { font-size: 18px; margin: 32px 0 10px; }
p, li { font-size: 15px; color: #262626; }
.lead { font-size: 16px; color: var(--muted); margin: 0 0 24px; }
.cta {
  display: inline-block;
  margin: 8px 12px 0 0;
  padding: 10px 16px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  font-size: 14px;
}
.cta-primary { background: var(--accent); color: #fff; }
.cta-ghost { border: 1px solid var(--line); color: var(--text); }
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin: 20px 0;
}
.card {
  display: block;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  text-decoration: none;
  color: inherit;
}
.card h3 { margin: 0 0 6px; font-size: 16px; }
.card p { margin: 0; color: var(--muted); font-size: 13px; }
.related { padding-left: 18px; }
.foot { color: var(--muted); font-size: 13px; }
.foot a { color: var(--muted); }
@media (max-width: 640px) {
  .bar { flex-direction: column; align-items: flex-start; }
  h1 { font-size: 24px; }
  main.wrap { padding: 24px 18px 36px; }
}