:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --accent: #2563eb;
  --border: #e2e8f0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
}

.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 32px 20px 64px;
}

header {
  margin-bottom: 28px;
}

.brand {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
}

h1 {
  margin: 8px 0 6px;
  font-size: 32px;
  line-height: 1.2;
}

.meta {
  color: var(--muted);
  font-size: 14px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
}

h2 {
  margin-top: 28px;
  margin-bottom: 10px;
  font-size: 20px;
}

h3 {
  margin-top: 18px;
  margin-bottom: 8px;
  font-size: 16px;
}

p,
li {
  color: #1e293b;
}

ul {
  padding-left: 22px;
}

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

.toc a {
  text-decoration: none;
}

.toc a:hover {
  text-decoration: underline;
}

.notice {
  margin-top: 20px;
  padding: 14px 16px;
  border-radius: 8px;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  font-size: 14px;
  color: #1e3a8a;
}

footer {
  margin-top: 24px;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 640px) {
  h1 {
    font-size: 26px;
  }

  .card {
    padding: 20px;
  }
}