:root {
  --bg: #f7f9fc;
  --text: #1f2937;
  --muted: #6b7280;
  --card: #ffffff;
  --line: #e5e7eb;
  --primary: #2563eb;
}

* {
  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: 1.6;
}

.container {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(6px);
}

.nav {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

nav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

nav a {
  text-decoration: none;
  color: var(--muted);
  font-size: 14px;
}

nav a[aria-current='page'],
nav a:hover {
  color: var(--text);
}

.hero {
  padding: 64px 0 24px;
}

.hero h1 {
  margin: 0;
  font-size: 44px;
  line-height: 1.2;
}

.hero p {
  margin: 12px 0 24px;
  color: var(--muted);
}

.cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  padding: 10px 16px;
  border-radius: 10px;
  text-decoration: none;
}

.btn.primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 40px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
}

.card h2 {
  margin-top: 0;
  font-size: 18px;
}

.card p {
  color: var(--muted);
  margin-bottom: 10px;
}

.card a {
  color: var(--primary);
  text-decoration: none;
}

.prose {
  padding: 32px 0 64px;
}

.prose h1 {
  margin-top: 0;
}

.prose h2 {
  margin-top: 24px;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #fff;
}

.site-footer p {
  margin: 0;
  padding: 16px 0;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 860px) {
  .cards {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 34px;
  }
}