:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --accent: #7c3aed;
  --success: #059669;
  --warning: #d97706;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 10px 40px rgba(15, 23, 42, 0.1);
}

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

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

.site-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 40px;
  background: var(--surface);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 50;
  flex-wrap: wrap;
  gap: 12px;
}

.site-nav .logo {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}

.site-nav .nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  align-items: center;
}

.site-nav .nav-links a {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.875rem;
  text-decoration: none;
}

.site-nav .nav-links a:hover,
.site-nav .nav-links a.active {
  color: var(--primary);
}

.hero {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 50%, #7c3aed 100%);
  color: #fff;
  text-align: center;
  padding: 72px 32px;
}

.hero h1 { font-size: 2.25rem; margin-bottom: 16px; }
.hero p { font-size: 1.1rem; opacity: 0.92; max-width: 720px; margin: 0 auto 28px; }

.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 10px 22px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9375rem;
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: 0.2s;
}

.btn:hover { text-decoration: none; opacity: 0.92; }

.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); color: #fff; }
.btn-white { background: #fff; color: var(--primary); }
.btn-outline-white { background: transparent; color: #fff; border-color: #fff; }
.btn-secondary { background: #e2e8f0; color: var(--text); }
.btn-success { background: var(--success); color: #fff; }

.section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 56px 32px;
}

.section-title { text-align: center; margin-bottom: 36px; }
.section-title h2 { font-size: 1.75rem; margin-bottom: 8px; }
.section-title p { color: var(--text-muted); }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

.card h3, .card h4 { margin-bottom: 10px; }
.card p, .card li { color: var(--text-muted); font-size: 0.9375rem; }
.card ul { padding-left: 20px; margin-top: 10px; }
.card li { margin-bottom: 6px; }

.feature-icon { font-size: 2rem; margin-bottom: 12px; }

.page-header {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 32px 0;
}

.page-header h1 { font-size: 1.85rem; margin-bottom: 8px; }
.page-header p { color: var(--text-muted); }

.breadcrumb {
  max-width: 1100px;
  margin: 0 auto;
  padding: 20px 32px 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

.alert {
  padding: 14px 18px;
  border-radius: 8px;
  margin: 24px 0;
  font-size: 0.9375rem;
}

.alert-info { background: var(--primary-light); color: #1e40af; }
.alert-success { background: #d1fae5; color: #065f46; }
.alert-warning { background: #fef3c7; color: #92400e; }

.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.9375rem; }
th, td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--bg); font-weight: 600; }
td { color: var(--text-muted); }

.steps {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin: 20px 0;
}

.step {
  flex: 1;
  min-width: 120px;
  text-align: center;
  padding: 16px 8px;
  border-radius: 8px;
  background: var(--bg);
  border: 1px solid var(--border);
}

.step.active { background: var(--primary-light); border-color: var(--primary); }

.step-num {
  width: 36px;
  height: 36px;
  line-height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  font-weight: 700;
  margin: 0 auto 10px;
}

.step-label { font-size: 0.8125rem; font-weight: 600; }

.related {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 32px 56px;
}

.related h3 { margin-bottom: 16px; }
.related-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.related-links a {
  display: inline-block;
  padding: 10px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
}

.related-links a:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.site-footer {
  text-align: center;
  padding: 28px;
  color: var(--text-muted);
  font-size: 0.875rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

@media (max-width: 768px) {
  .site-nav { padding: 14px 20px; }
  .hero h1 { font-size: 1.6rem; }
  .section, .page-header, .breadcrumb, .related { padding-left: 20px; padding-right: 20px; }
  .two-col { grid-template-columns: 1fr; }
}