:root {
  color-scheme: light;
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  color: #1f2937;
  background: #f5f7fb;
}
body { margin: 0; }
main {
  max-width: 860px;
  margin: 48px auto;
  padding: 40px;
  background: #fff;
  border-radius: 18px;
  box-shadow: 0 12px 36px rgba(31, 41, 55, .08);
}
h1 { color: #b91c1c; }
h2 { margin-top: 32px; }
p, li { line-height: 1.75; }
nav a, a { color: #b91c1c; }
nav { display: flex; gap: 20px; flex-wrap: wrap; margin-bottom: 32px; }
.note { padding: 16px 18px; background: #fff7ed; border-left: 4px solid #f97316; }
footer { margin-top: 40px; color: #6b7280; font-size: 14px; }
@media (max-width: 700px) {
  main { margin: 0; padding: 24px; border-radius: 0; }
}