:root {
  color-scheme: light dark;
  --bg: #0a1018;
  --bg-card: rgba(255, 255, 255, 0.06);
  --text: #f5f5f7;
  --text-secondary: rgba(255, 255, 255, 0.65);
  --accent: #4db8ff;
  --border: rgba(255, 255, 255, 0.12);
  --max-width: 760px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f8fc;
    --bg-card: #ffffff;
    --text: #1d1d1f;
    --text-secondary: #6e6e73;
    --accent: #0077cc;
    --border: rgba(0, 0, 0, 0.08);
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: linear-gradient(180deg, var(--bg) 0%, #121c28 100%);
  color: var(--text);
  line-height: 1.65;
  min-height: 100vh;
}

@media (prefers-color-scheme: light) {
  body {
    background: linear-gradient(180deg, #f4f8fc 0%, #e8f0f8 100%);
  }
}

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 20px 80px;
}

header {
  margin-bottom: 32px;
}

.badge {
  display: inline-block;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

h1 {
  margin: 16px 0 8px;
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1.15;
}

.subtitle {
  margin: 0;
  color: var(--text-secondary);
  font-size: 17px;
}

nav.top {
  margin-top: 20px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

nav.top a {
  color: var(--accent);
  text-decoration: none;
  font-size: 14px;
}

nav.top a:hover {
  text-decoration: underline;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 22px 24px;
  margin-bottom: 18px;
}

.card h2 {
  margin: 0 0 12px;
  font-size: 20px;
}

.card h3 {
  margin: 18px 0 8px;
  font-size: 16px;
}

.card p,
.card li {
  color: var(--text-secondary);
}

.card ul,
.card ol {
  padding-left: 1.2em;
}

.card li + li {
  margin-top: 6px;
}

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

footer {
  margin-top: 36px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  color: var(--text-secondary);
  font-size: 14px;
}

.contact {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
}

.meta {
  font-size: 13px;
  color: var(--text-secondary);
}