:root {
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #6b7280;
  --accent: #ff0a00;
  --border: #e5e7eb;
  --max-width: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0b0d;
    --fg: #f4f4f5;
    --muted: #9ca3af;
    --border: #27272a;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px;
}

header.site {
  border-bottom: 1px solid var(--border);
}

header.site .container {
  padding-top: 24px;
  padding-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

header.site a.brand {
  font-weight: 600;
  font-size: 18px;
  color: var(--fg);
  text-decoration: none;
}

header.site nav a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 20px;
  font-size: 14px;
}

header.site nav a:hover { color: var(--fg); }

h1 { font-size: 36px; line-height: 1.2; margin: 0 0 16px; }
h2 { font-size: 22px; margin: 32px 0 12px; }
p { margin: 0 0 16px; }

a { color: var(--accent); }

.lead {
  font-size: 19px;
  color: var(--muted);
  margin-bottom: 32px;
}

.cta {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 12px 24px;
  border-radius: 10px;
  text-decoration: none;
  font-weight: 600;
  margin-top: 8px;
}

.cta:hover { opacity: 0.9; }

.features {
  list-style: none;
  padding: 0;
  margin: 32px 0;
}

.features li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.features li:last-child { border-bottom: none; }

footer.site {
  border-top: 1px solid var(--border);
  margin-top: 64px;
}

footer.site .container {
  padding-top: 24px;
  padding-bottom: 24px;
  font-size: 14px;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

footer.site a { color: var(--muted); margin-left: 16px; text-decoration: none; }
footer.site a:first-of-type { margin-left: 0; }

[lang="en"] .zh, [lang="zh"] .en { display: none; }

@media (max-width: 480px) {
  .container { padding: 32px 20px; }
  h1 { font-size: 28px; }
  header.site nav a { margin-left: 14px; }
  footer.site .container { flex-direction: column; }
}