:root {
  --primary: #0b5ed7;
  --dark: #0f172a;
  --text: #1f2937;
  --muted: #6b7280;
  --bg: #f8fafc;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
  color: var(--text);
  background: var(--white);
  line-height: 1.6;
}

.container {
  width: min(1100px, 92%);
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid #e5e7eb;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
}

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--dark);
}

.nav {
  display: flex;
  gap: 18px;
}

.nav a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.95rem;
}

.nav a:hover {
  color: var(--primary);
}

.hero {
  padding: 90px 0 80px;
  background: linear-gradient(135deg, #eff6ff, #ffffff);
}

.tag {
  color: var(--primary);
  font-weight: 600;
  margin: 0 0 8px;
}

.hero h1 {
  margin: 0;
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  color: var(--dark);
}

.subtitle {
  margin-top: 14px;
  max-width: 720px;
  color: var(--muted);
}

.btn {
  display: inline-block;
  margin-top: 20px;
  padding: 12px 22px;
  background: var(--primary);
  color: var(--white);
  text-decoration: none;
  border-radius: 10px;
  font-weight: 600;
}

.btn:hover {
  opacity: 0.92;
}

.section {
  padding: 72px 0;
}

.section-alt {
  background: var(--bg);
}

h2 {
  margin-top: 0;
  margin-bottom: 14px;
  font-size: 1.8rem;
  color: var(--dark);
}

.cards {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.card {
  background: var(--white);
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  padding: 20px;
}

.card h3 {
  margin-top: 0;
  margin-bottom: 8px;
  color: var(--dark);
}

.list {
  padding-left: 18px;
  margin: 10px 0 0;
}

.site-footer {
  background: #0b1220;
  color: #cbd5e1;
  padding: 18px 0;
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 900px) {
  .cards {
    grid-template-columns: 1fr;
  }

  .nav {
    gap: 12px;
    flex-wrap: wrap;
    justify-content: flex-end;
  }
}