:root {
  color-scheme: light dark;
  --bg: #f8fafc;
  --bg-grad-1: #e2e8f0;
  --bg-grad-2: #ffffff;
  --surface: rgba(255, 255, 255, 0.92);
  --surface-solid: rgba(255, 255, 255, 0.95);
  --border: rgba(15, 23, 42, 0.08);
  --text: #0f172a;
  --text-muted: #334155;
  --text-subtle: #475569;
  --accent: #1d4ed8;
  --accent-soft: rgba(29, 78, 216, 0.1);
  --shadow-lg: 0 24px 60px rgba(15, 23, 42, 0.07);
  --shadow-md: 0 12px 28px rgba(15, 23, 42, 0.05);
  --item-bg: #f8fafc;
  --item-ring: rgba(15, 23, 42, 0.04);

  color: var(--text);
  background: var(--bg);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.7;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --bg-grad-1: #111827;
    --bg-grad-2: #0b1220;
    --surface: rgba(17, 24, 39, 0.85);
    --surface-solid: rgba(17, 24, 39, 0.9);
    --border: rgba(148, 163, 184, 0.14);
    --text: #e2e8f0;
    --text-muted: #cbd5e1;
    --text-subtle: #94a3b8;
    --accent: #60a5fa;
    --accent-soft: rgba(96, 165, 250, 0.15);
    --shadow-lg: 0 24px 60px rgba(0, 0, 0, 0.45);
    --shadow-md: 0 12px 28px rgba(0, 0, 0, 0.35);
    --item-bg: #0f172a;
    --item-ring: rgba(148, 163, 184, 0.12);
  }
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at top, var(--bg-grad-1) 0%, var(--bg) 40%, var(--bg-grad-2) 100%);
  color: var(--text);
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background: radial-gradient(circle at top left, rgba(59, 130, 246, 0.08), transparent 25%),
              radial-gradient(circle at bottom right, rgba(16, 185, 129, 0.06), transparent 22%);
  pointer-events: none;
}
main {
  position: relative;
  max-width: 980px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}
.breadcrumb {
  margin: 0 0 1rem;
  font-size: 0.9rem;
}
.breadcrumb a {
  color: var(--text-subtle);
  text-decoration: none;
}
.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--accent);
  text-decoration: underline;
}
header {
  margin-bottom: 2rem;
  padding: 1.5rem 1.5rem 1.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 1.25rem;
  box-shadow: var(--shadow-lg);
  backdrop-filter: blur(6px);
}
h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(2rem, 3vw, 2.75rem);
  letter-spacing: -0.03em;
}
p {
  margin: 0 0 1rem;
  color: var(--text-muted);
}
.notice {
  margin-top: 1rem;
  color: var(--text-subtle);
  font-size: 0.98rem;
}
.toc {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1.25rem;
  padding: 0;
  list-style: none;
}
.toc a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  background: var(--accent-soft);
  border: 1px solid var(--border);
  color: var(--accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.toc a:hover,
.toc a:focus-visible {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}
.toc .count {
  opacity: 0.75;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
dl {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.5rem;
}
dt {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin: 0;
  scroll-margin-top: 1.5rem;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
}
dt .count {
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  background: var(--item-bg);
  border: 1px solid var(--border);
  color: var(--text-subtle);
  font-size: 0.8rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
dd {
  margin: 0;
  padding: 1.25rem;
  background: var(--surface-solid);
  border: 1px solid var(--border);
  border-radius: 1rem;
  box-shadow: var(--shadow-md);
}
dd ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.75rem;
  column-gap: 2rem;
}
dd ul li {
  padding: 0.65rem 0.85rem;
  border-radius: 0.85rem;
  background: var(--item-bg);
  box-shadow: inset 0 0 0 1px var(--item-ring);
}
dd ul li a {
  color: var(--accent);
  text-decoration: none;
}
dd ul li a:hover,
dd ul li a:focus-visible {
  text-decoration: underline;
}
.source-card ul {
  margin: 0;
  padding-left: 1.25rem;
}
.source-card li {
  margin-bottom: 0.35rem;
}
.source-card a {
  color: var(--accent);
}
footer {
  margin-top: 2rem;
  padding: 1rem 1.25rem;
  color: var(--text-subtle);
  text-align: center;
  font-size: 0.95rem;
}
footer a {
  color: var(--text-subtle);
}
footer a:hover,
footer a:focus-visible {
  color: var(--accent);
}
@media (min-width: 640px) {
  dd ul {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
@media (min-width: 1024px) {
  main {
    padding: 3rem 2rem 4rem;
  }
  dd ul {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}