:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: min(960px, 92%);
  margin: 0 auto;
}

header {
  background: #0f172a;
  color: #fff;
  padding: 18px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.site-title {
  margin: 0;
  font-size: 1.25rem;
}

nav a {
  color: #dbeafe;
  text-decoration: none;
  margin-left: 14px;
}

nav a:hover {
  color: #fff;
  text-decoration: underline;
}

main {
  padding: 34px 0 56px;
  flex: 1;
}

.hero {
  background: linear-gradient(135deg, #dbeafe, #eff6ff);
  border: 1px solid #bfdbfe;
  border-radius: 14px;
  padding: 24px;
  margin-bottom: 22px;
}

.hero h2 {
  margin: 0 0 10px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
}

.card h3 {
  margin-top: 0;
}

.btn {
  display: inline-block;
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid var(--accent);
  color: var(--accent);
  text-decoration: none;
  font-size: 0.95rem;
}

.btn:hover {
  background: #eff6ff;
}

footer {
  border-top: 1px solid var(--border);
  background: #fff;
  padding: 16px 0 22px;
  color: var(--muted);
  font-size: 0.92rem;
}

footer a {
  color: #1d4ed8;
}

.muted {
  color: var(--muted);
}