:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --text: #1f2328;
  --muted: #59636e;
  --card: #f6f8fa;
  --border: #d0d7de;
  --link: #0969da;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --text: #e6edf3;
    --muted: #9ea7b3;
    --card: #161b22;
    --border: #30363d;
    --link: #58a6ff;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

main {
  max-width: 860px;
  margin: 0 auto;
  padding: 28px 20px 60px;
}

header {
  padding: 18px 20px;
  border: 1px solid var(--border);
  background: var(--card);
  border-radius: 10px;
}

h1 {
  margin: 0 0 8px;
  font-size: 1.8rem;
}

h2 {
  margin-top: 34px;
  margin-bottom: 10px;
  font-size: 1.2rem;
}

p,
ul {
  margin-top: 10px;
  margin-bottom: 10px;
}

ul {
  padding-left: 20px;
}

small,
.meta {
  color: var(--muted);
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

footer {
  margin-top: 30px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  color: var(--muted);
}