:root {
  --bg: #FAFAF8;
  --surface: #FFFFFF;
  --primary: #E86B4A;
  --text: #2D3142;
  --text-muted: #6B7280;
  --border: #E5E7EB;
  --max-width: 760px;
  --radius: 16px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0F1117;
    --surface: #1A1D27;
    --primary: #F08B6E;
    --text: #F3F4F6;
    --text-muted: #9CA3AF;
    --border: #2A2D37;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px 96px;
}
header { margin-bottom: 40px; }
h1 {
  font-size: 2.25rem;
  font-weight: 800;
  margin: 0 0 8px;
  color: var(--primary);
  letter-spacing: -0.02em;
}
h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 32px 0 12px;
  letter-spacing: -0.01em;
}
h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 24px 0 8px;
}
p { margin: 0 0 16px; }
ul, ol { margin: 0 0 16px; padding-left: 24px; }
li { margin-bottom: 6px; }
.lead {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin: 0;
}
.muted {
  color: var(--text-muted);
  font-size: 0.875rem;
}
a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}
a:hover { text-decoration: underline; }
.cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin: 24px 0 48px;
}
@media (min-width: 640px) {
  .cards { grid-template-columns: 1fr 1fr; }
}
.card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: transform 0.15s ease, border-color 0.15s ease;
  color: var(--text);
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--primary);
  text-decoration: none;
}
.card h2 { margin: 0 0 8px; font-size: 1.25rem; color: var(--text); }
.card p { margin: 0; color: var(--text-muted); font-size: 0.95rem; }
article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  margin-top: 24px;
}
@media (max-width: 640px) {
  article { padding: 24px 20px; }
}
.toc {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
  margin: 16px 0 24px;
}
.toc ol { margin: 0; padding-left: 20px; }
.toc li { font-size: 0.95rem; }
.back {
  display: inline-block;
  margin-bottom: 16px;
  font-size: 0.95rem;
}
footer {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.95rem;
}
footer p { margin: 4px 0; }
strong { color: var(--text); font-weight: 600; }