:root {
  --primary: #2f54eb;
  --primary-dark: #1d39c4;
  --ink: #1f2430;
  --text: #374151;
  --muted: #6b7280;
  --bg: #ffffff;
  --bg-soft: #f5f7fb;
  --border: #e5e7eb;
  --radius: 10px;
  --maxw: 960px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  color: var(--text);
  line-height: 1.75;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { font-size: 20px; font-weight: 700; color: var(--ink); }
.brand .accent { color: var(--primary); }
.nav-links { display: flex; gap: 22px; }
.nav-links a { color: var(--text); font-size: 15px; }
.nav-links a:hover { color: var(--primary); text-decoration: none; }
.nav-links a.active { color: var(--primary); font-weight: 600; }

/* Hero */
.hero { background: linear-gradient(135deg, #2f54eb 0%, #1d39c4 100%); color: #fff; padding: 72px 0; }
.hero h1 { font-size: 36px; line-height: 1.35; margin-bottom: 16px; }
.hero p { font-size: 18px; opacity: 0.95; max-width: 740px; }
.hero .tags { margin-top: 24px; display: flex; flex-wrap: wrap; gap: 10px; }
.hero .tag { background: rgba(255,255,255,0.18); border: 1px solid rgba(255,255,255,0.3); padding: 4px 12px; border-radius: 999px; font-size: 13px; }

/* Main sections */
main { padding: 48px 0 72px; }
section { margin-bottom: 48px; }
h2 { font-size: 26px; color: var(--ink); margin-bottom: 16px; }
h3 { font-size: 18px; color: var(--ink); margin-bottom: 8px; }
p { margin-bottom: 12px; }
.lead { font-size: 17px; color: var(--ink); }
.page-title { padding: 40px 0 8px; border-bottom: 1px solid var(--border); margin-bottom: 32px; }
.page-title h1 { font-size: 30px; color: var(--ink); margin-bottom: 8px; }
.page-title p { color: var(--muted); }

/* Cards */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.card { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.card .num { color: var(--primary); font-weight: 700; margin-bottom: 6px; font-size: 14px; }
.card h3 { font-size: 17px; }
.card p { font-size: 14px; color: var(--muted); margin-bottom: 0; }

/* Tables */
table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 15px; }
th, td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; }
th { background: var(--bg-soft); color: var(--ink); }
tr:nth-child(even) td { background: #fafbfd; }

/* Callout */
.callout { background: #eef4ff; border-left: 4px solid var(--primary); border-radius: 6px; padding: 16px 20px; margin: 16px 0; }
.callout p:last-child { margin-bottom: 0; }

/* Lists */
ul, ol { margin: 0 0 16px 22px; }
li { margin-bottom: 6px; }

/* Footer */
.site-footer { background: var(--ink); color: #cbd5e1; padding: 40px 0; font-size: 14px; }
.site-footer .brand { color: #fff; }
.site-footer .relations { margin-top: 12px; color: #94a3b8; }

@media (max-width: 640px) {
  .nav-links { gap: 14px; }
  .nav-links a { font-size: 14px; }
  .hero { padding: 48px 0; }
  .hero h1 { font-size: 28px; }
  h2 { font-size: 22px; }
  .page-title h1 { font-size: 26px; }
}