:root {
  --bg: #070c18;
  --panel: #0d1424;
  --panel-2: #121c31;
  --text: #f4f7ff;
  --muted: #a9b7d3;
  --line: rgba(255, 255, 255, 0.12);
  --brand: #56a3ff;
  --brand-2: #7dc8ff;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 85% -10%, rgba(86, 163, 255, 0.34), transparent 55%),
    radial-gradient(900px 500px at 0% 10%, rgba(125, 200, 255, 0.18), transparent 60%),
    var(--bg);
  line-height: 1.6;
}

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

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(8px);
  background: rgba(7, 12, 24, 0.75);
  border-bottom: 1px solid var(--line);
}

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

.brand img { height: 34px; width: auto; display: block; }

.cta, .hero-btn {
  display: inline-block;
  text-decoration: none;
  color: #051327;
  background: linear-gradient(90deg, var(--brand), var(--brand-2));
  font-weight: 700;
  border-radius: 12px;
  transition: transform .2s ease, box-shadow .2s ease;
}

.cta { padding: 10px 16px; font-size: 14px; }
.hero-btn { padding: 13px 22px; font-size: 16px; }

.cta:hover, .hero-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(86, 163, 255, 0.35);
}

.hero { padding: 78px 0 56px; }
.hero-inner {
  background: linear-gradient(145deg, rgba(13, 20, 36, 0.95), rgba(18, 28, 49, 0.92));
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 56px 42px;
}

h1, h2 { margin: 0 0 14px; line-height: 1.25; }
h1 { font-size: clamp(28px, 4vw, 46px); }
h2 { font-size: clamp(22px, 3vw, 32px); }
p { margin: 0; color: var(--muted); }

.section { padding: 20px 0 8px; }
.section-sub { margin-top: 6px; }

.grid {
  margin-top: 24px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.card {
  text-decoration: none;
  color: var(--text);
  background: linear-gradient(180deg, rgba(18, 28, 49, 0.9), rgba(13, 20, 36, 0.95));
  border: 1px solid var(--line);
  border-radius: 16px;
  min-height: 150px;
  padding: 20px 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 12px;
  transition: transform .22s ease, border-color .22s ease, box-shadow .22s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(125, 200, 255, 0.5);
  box-shadow: 0 16px 30px rgba(0, 0, 0, 0.34);
}

.card img {
  width: 42px;
  height: 42px;
  display: block;
  filter: invert(1);
}

.card span { font-size: 15px; font-weight: 600; text-align: center; }

.seo-copy { padding-bottom: 64px; }
.footer { border-top: 1px solid var(--line); padding: 20px 0 34px; }
.footer a { color: var(--brand-2); }

@media (max-width: 960px) {
  .grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (max-width: 720px) {
  .topbar-inner { height: 64px; }
  .brand img { height: 28px; }
  .hero { padding-top: 48px; }
  .hero-inner { padding: 34px 22px; border-radius: 16px; }
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
  .card { min-height: 130px; }
}