:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --bg-soft: #f6f7f9;
  --fg: #1b1f24;
  --muted: #5b6470;
  --border: #e3e6ea;
  --accent: #3b5bdb;
  --code-bg: #f2f4f7;
  --sidebar-width: 17rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101317;
    --bg-soft: #161b21;
    --fg: #e6e9ee;
    --muted: #9aa4b2;
    --border: #262d36;
    --accent: #86a0ff;
    --code-bg: #1b212a;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 2;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.brand {
  color: var(--fg);
  font-weight: 600;
}

.repo {
  font-size: 0.9rem;
}

.shell {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: 2rem;
  max-width: 80rem;
  margin: 0 auto;
  padding: 1.5rem;
}

.shell.wide {
  grid-template-columns: minmax(0, 1fr);
  max-width: 72rem;
}

.sidebar {
  position: sticky;
  top: 4rem;
  align-self: start;
  max-height: calc(100vh - 5rem);
  overflow: auto;
  font-size: 0.92rem;
}

.nav-home {
  margin: 0 0 0.75rem;
  font-weight: 600;
}

.nav-group h2 {
  margin: 1.25rem 0 0.35rem;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-group ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-group li {
  margin: 0.15rem 0;
}

.nav-group a,
.nav-home a {
  display: block;
  padding: 0.15rem 0.5rem;
  border-radius: 0.35rem;
  color: var(--fg);
}

.nav-group a:hover {
  background: var(--bg-soft);
  text-decoration: none;
}

a[aria-current="page"] {
  background: var(--bg-soft);
  font-weight: 600;
}

.content {
  min-width: 0;
  max-width: 52rem;
}

.content h1 {
  margin-top: 0;
  font-size: 2rem;
  line-height: 1.2;
}

.content h2 {
  margin-top: 2.5rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--border);
}

.content h3 {
  margin-top: 2rem;
}

.content code {
  padding: 0.1rem 0.3rem;
  border-radius: 0.25rem;
  background: var(--code-bg);
  font-size: 0.9em;
}

.content pre {
  padding: 1rem;
  border-radius: 0.5rem;
  background: var(--code-bg);
  overflow: auto;
}

.content pre code {
  padding: 0;
  background: none;
}

.content table {
  display: block;
  width: 100%;
  border-collapse: collapse;
  overflow: auto;
}

.content th,
.content td {
  padding: 0.4rem 0.6rem;
  border: 1px solid var(--border);
  text-align: left;
}

.content blockquote {
  margin: 1.5rem 0;
  padding: 0.25rem 1rem;
  border-left: 3px solid var(--border);
  color: var(--muted);
}

.content img {
  max-width: 100%;
}

.hero {
  padding-bottom: 1rem;
}

.hero h1 {
  font-size: 2.5rem;
}

.hero p {
  max-width: 40rem;
  color: var(--muted);
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.button {
  display: inline-block;
  padding: 0.5rem 0.9rem;
  border-radius: 0.4rem;
  background: var(--accent);
  color: var(--bg);
  font-weight: 600;
}

.button:hover {
  opacity: 0.9;
  text-decoration: none;
}

.button.ghost {
  border: 1px solid var(--border);
  background: none;
  color: var(--accent);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(16rem, 1fr));
  gap: 0.75rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.card a {
  display: block;
  height: 100%;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 0.6rem;
  background: var(--bg-soft);
  color: var(--fg);
}

.card a:hover {
  border-color: var(--accent);
  text-decoration: none;
}

.card h3 {
  margin: 0 0 0.4rem;
  font-size: 1rem;
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.links {
  padding-left: 1.1rem;
}

.footer {
  max-width: 80rem;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
}

@media (max-width: 900px) {
  .shell {
    grid-template-columns: minmax(0, 1fr);
    gap: 1rem;
    padding: 1rem;
  }

  .sidebar {
    position: static;
    max-height: none;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
  }
}