:root {
  --bg: #f7f7f5;
  --surface: #ffffff;
  --text: #1f2421;
  --text-muted: #5a615e;
  --accent: #1b5e3a;
  --accent-soft: rgba(27, 94, 58, 0.08);
  --border: rgba(0, 0, 0, 0.08);
  --code-bg: rgba(0, 0, 0, 0.04);
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.site-header {
  padding: 24px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.site-header-inner {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.brand {
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--accent);
  text-decoration: none;
}

.brand-sub {
  margin-left: 8px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0;
}

.nav {
  display: flex;
  gap: 20px;
  font-size: 14px;
}

.nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 600;
}

.nav a:hover,
.nav a.active {
  color: var(--accent);
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.doc-meta {
  color: var(--text-muted);
  font-size: 14px;
  margin-bottom: 24px;
}

h1 {
  font-size: 30px;
  line-height: 1.3;
  font-weight: 800;
  letter-spacing: -0.8px;
  margin: 0 0 8px;
}

h2 {
  font-size: 22px;
  line-height: 1.35;
  font-weight: 800;
  letter-spacing: -0.3px;
  margin: 48px 0 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

h3 {
  font-size: 17px;
  font-weight: 700;
  margin: 28px 0 10px;
}

p,
ul,
ol {
  margin: 0 0 16px;
}

ul,
ol {
  padding-left: 24px;
}

li {
  margin-bottom: 6px;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover {
  text-decoration: none;
}

code {
  padding: 1px 6px;
  font-size: 0.92em;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  background: var(--code-bg);
  border-radius: 4px;
}

.note {
  margin: 24px 0;
  padding: 16px 18px;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  border-radius: 6px;
  color: var(--text);
  font-size: 14.5px;
}

.note strong {
  color: var(--accent);
}

.site-footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 20px 40px;
  color: var(--text-muted);
  font-size: 13px;
  text-align: center;
}

@media (max-width: 520px) {
  h1 {
    font-size: 26px;
  }
  h2 {
    font-size: 20px;
  }
  main {
    padding-top: 24px;
  }
}