:root {
  --bg: #ffffff;
  --text: #0f172a;
  --muted: #6b7280;
  --muted-weak: #9ca3af;
  --card: #f8fafc;
  --border: #e5e7eb;
  --primary: #1260ff;
  --primary-weak: rgba(18, 96, 255, 0.2);
}

.dark {
  --bg: #212121;
  --text: #e5e7eb;
  --muted: #9ca3af;
  --muted-weak: #6b7280;
  --card: #3e3f36;
  --border: #1f2937;
  --primary: #7aa7ff;
  --primary-weak: rgba(122, 167, 255, 0.2);
}

body { background: var(--bg); color: var(--text); }
.card { background: var(--card); border: 1px solid var(--border); }
.muted { color: var(--muted); }
.muted-weak { color: var(--muted-weak); }
.link-primary { color: var(--primary); }
.link-primary:hover { color: var(--text); }
.card-link {
  display: block;
  transition: border-color 150ms ease, box-shadow 150ms ease, transform 150ms ease;
}
.card-link:hover {
  border-color: var(--primary);
  box-shadow: 0 12px 30px rgba(59, 130, 246, 0.18);
  transform: translateY(-1px);
}
.toc-link.active {
  color: var(--primary);
  font-weight: 600;
}
.theme-icon { display: none; }
:root .theme-sun { display: inline; }
.dark .theme-sun { display: none; }
.dark .theme-moon { display: inline; }