:root {
  --ink: #1a2b3c;
  --muted: #5a6b7c;
  --line: #d8e2ec;
  --bg: #f3f7fb;
  --card: #ffffff;
  --brand: #1e6bb8;
  --brand-deep: #154a7a;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Source Han Sans SC", "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 480px at 10% -10%, #cfe4f8 0%, transparent 55%),
    radial-gradient(900px 420px at 100% 0%, #d9efe8 0%, transparent 50%),
    var(--bg);
  line-height: 1.7;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 820px; margin: 0 auto; padding: 28px 18px 64px; }
.topnav {
  display: flex; flex-wrap: wrap; gap: 12px 18px; align-items: center;
  margin-bottom: 24px; font-size: 14px;
}
.brand {
  font-weight: 700; color: var(--brand-deep); margin-right: auto; font-size: 16px;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 28px 24px;
  box-shadow: 0 8px 28px rgba(30, 74, 122, 0.06);
}
h1 { margin: 0 0 8px; font-size: clamp(24px, 4vw, 30px); letter-spacing: 0.02em; }
.meta { color: var(--muted); font-size: 13px; margin-bottom: 22px; }
h2 { margin: 28px 0 10px; font-size: 18px; color: var(--brand-deep); }
p, li { font-size: 15px; }
ul { padding-left: 1.2em; }
.footer {
  margin-top: 28px; text-align: center; color: var(--muted); font-size: 12px;
}
@media (max-width: 640px) {
  .card { padding: 20px 16px; }
}