:root {
  --bg: #f0f2f5;
  --surface: #ffffff;
  --surface-muted: #f8fafc;
  --line: #e2e8f0;
  --text: #1f2937;
  --muted: #64748b;
  --primary: #3b82f6;
  --accent: #7c3aed;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: radial-gradient(circle at 20% 0%, #f9fbff 0%, var(--bg) 42%, #eceff4 100%);
  color: var(--text);
}

.home {
  min-height: 100vh;
  padding: 24px clamp(14px, 3vw, 34px) 28px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.top-nav {
  display: flex;
  align-items: center;
  padding: 0 4px;
}

.back-series {
  font-size: 13px;
  font-weight: 700;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 6px 12px;
  background: var(--surface);
  transition: color .15s, border-color .15s;
}

.back-series:hover {
  color: var(--primary);
  border-color: var(--primary);
}

.brand {
  text-align: center;
  padding-top: 8px;
}

.brand h1 {
  margin: 0;
  font-size: clamp(28px, 4vw, 46px);
  font-weight: 800;
  letter-spacing: 0.2px;
}

.brand p {
  margin: 8px 0 0;
  font-size: 16px;
  color: var(--muted);
}

.grid {
  width: min(1320px, 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.card {
  min-height: 90px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-decoration: none;
  color: inherit;
  font-size: clamp(22px, 2.4vw, 32px);
  font-weight: 700;
  box-shadow: 0 6px 18px rgba(15, 23, 42, 0.06);
  transition: transform 140ms ease, box-shadow 140ms ease, border-color 140ms ease;
}

.card:hover {
  transform: translateY(-2px);
  border-color: #bfd3ff;
  box-shadow: 0 14px 28px rgba(59, 130, 246, 0.12);
}

.card .icon {
  font-size: 22px;
  opacity: 0.9;
}

.card.coming {
  color: #94a3b8;
  background: var(--surface-muted);
  cursor: not-allowed;
}

.footer {
  margin-top: auto;
  text-align: center;
  color: #94a3b8;
  font-size: 14px;
}

@media (max-width: 860px) {
  .grid { grid-template-columns: 1fr; }
  .card { min-height: 82px; }
}