:root {
  --bg-dark: #030a22;
  --bg-dark-2: #071637;
  --primary: #46a4ff;
  --text: #1b2430;
  --text-light: #dce8ff;
  --muted: #6b7280;
  --card-border: #e8eef7;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
  color: var(--text);
  background: #f6f8fc;
  line-height: 1.7;
}

.container {
  width: min(1120px, 92%);
  margin: 0 auto;
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 10;
  background: rgba(3, 10, 34, 0.85);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(150deg, #53c4ff, #2265ff);
  color: #fff;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 13px;
  box-shadow: 0 8px 24px rgba(22, 116, 255, 0.4);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-text strong {
  color: #fff;
  font-size: 18px;
}

.brand-text span {
  color: #9bb6f7;
  font-size: 12px;
  letter-spacing: 1px;
}

.nav a {
  color: #c7d7ff;
  text-decoration: none;
  margin-left: 20px;
  font-size: 14px;
}

.nav a:hover {
  color: #fff;
}

.hero {
  min-height: 86vh;
  background:
    radial-gradient(circle at 30% 40%, rgba(52, 142, 255, 0.2), transparent 45%),
    linear-gradient(150deg, var(--bg-dark), var(--bg-dark-2));
  position: relative;
  display: flex;
  align-items: center;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.06) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.25;
}

.hero-content {
  position: relative;
  padding-top: 84px;
  padding-bottom: 84px;
  text-align: center;
  color: var(--text-light);
}

.hero-tag {
  display: inline-block;
  margin: 0 0 10px;
  padding: 5px 14px;
  font-size: 12px;
  border: 1px solid rgba(142, 186, 255, 0.45);
  border-radius: 999px;
  color: #cde2ff;
}

.hero h1 {
  margin: 0;
  font-size: clamp(34px, 6vw, 62px);
  line-height: 1.14;
  color: #fff;
}

.hero-subtitle {
  margin: 22px auto 0;
  max-width: 760px;
  color: #c4d6f9;
  font-size: 18px;
}

.btn-primary {
  margin-top: 28px;
  display: inline-block;
  background: linear-gradient(135deg, #45b3ff, #2e7bff);
  color: #fff;
  text-decoration: none;
  border-radius: 10px;
  padding: 10px 22px;
  font-weight: 600;
}

.btn-primary:hover {
  filter: brightness(1.05);
}

.section {
  padding: 76px 0;
}

.section h2 {
  margin: 0 0 10px;
  font-size: clamp(24px, 3vw, 34px);
}

.section-intro {
  margin: 0 0 30px;
  color: var(--muted);
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.card {
  background: #fff;
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(27, 36, 48, 0.05);
}

.card h3 {
  margin: 0 0 10px;
  font-size: 28px;
  line-height: 1.2;
  color: #1f3c70;
}

.card p {
  margin: 0;
  color: #4b5563;
}

.about {
  background: #fff;
  border-top: 1px solid #edf2fb;
  border-bottom: 1px solid #edf2fb;
}

.site-footer {
  background: linear-gradient(160deg, #020a22, #06112f);
  color: #bcc8e6;
  text-align: center;
  padding: 34px 0;
  font-size: 14px;
}

.site-footer p {
  margin: 4px 0;
}

.site-footer a {
  color: #c9dcff;
  text-decoration: none;
}

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

  .nav {
    display: none;
  }

  .hero-subtitle {
    font-size: 16px;
  }
}