:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #2563eb;
  --border: #e5e7eb;
  --shadow: 0 8px 30px rgba(17, 24, 39, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

.page {
  max-width: 860px;
  margin: 0 auto;
  padding: 24px 16px 48px;
}

.topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.brand {
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 14px;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
}

.nav-links a.active,
.nav-links a:hover {
  color: var(--primary);
}

.lang-switch {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.lang-switch label {
  font-size: 13px;
  color: var(--muted);
}

.lang-switch select {
  min-width: 148px;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  font-size: 14px;
  color: var(--text);
}

.card {
  background: var(--card);
  border-radius: 18px;
  box-shadow: var(--shadow);
  padding: 28px 24px;
}

h1 {
  margin: 0 0 8px;
  font-size: 28px;
  line-height: 1.25;
}

.updated {
  margin: 0 0 24px;
  color: var(--muted);
  font-size: 14px;
}

section {
  margin-bottom: 24px;
}

section h2 {
  margin: 0 0 10px;
  font-size: 18px;
}

section p {
  margin: 0 0 10px;
  font-size: 15px;
}

section ul {
  margin: 0;
  padding-left: 20px;
}

section li {
  margin-bottom: 8px;
  font-size: 15px;
}

.footer-note {
  margin-top: 28px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 640px) {
  .card {
    padding: 22px 18px;
  }

  h1 {
    font-size: 24px;
  }
}