:root {
  --bg:         #ffffff;
  --text:       #1a1a1a;
  --muted:      #6b7280;
  --border:     #e5e7eb;
  --accent:     #2563eb;
  --accent-bg:  #eff6ff;
  --code-bg:    #f9fafb;
  --sidebar-w:  220px;
  --header-h:   48px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

/* ── Header ─────────────────────────────────── */

header {
  position: sticky;
  top: 0;
  z-index: 10;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0 1.5rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.brand:hover { color: var(--accent); }

.sep {
  color: var(--border);
  font-weight: 300;
  user-select: none;
  padding: 0 0.1rem;
}

.bc {
  font-size: 0.875rem;
  color: var(--muted);
}

.bc a {
  color: var(--muted);
  text-decoration: none;
}

.bc a:hover { color: var(--accent); }

/* ── Layout ─────────────────────────────────── */

.wrap {
  display: flex;
  min-height: calc(100vh - var(--header-h));
}

/* ── Sidebar ─────────────────────────────────── */

.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  border-right: 1px solid var(--border);
  padding: 1.5rem 0.75rem;
  font-size: 0.875rem;
  overflow-y: auto;
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
}

.sidebar a {
  display: block;
  padding: 0.3rem 0.6rem;
  border-radius: 5px;
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  margin-bottom: 0.1rem;
}

.sidebar a:hover  { background: var(--code-bg); }
.sidebar a.active { background: var(--accent-bg); color: var(--accent); }

.sidebar ul {
  list-style: none;
  margin: 0.15rem 0 0.75rem;
}

.sidebar ul li a {
  font-weight: 400;
  color: var(--muted);
  padding-left: 1.1rem;
}

.sidebar ul li a:hover  { color: var(--text); background: var(--code-bg); }
.sidebar ul li a.active { color: var(--accent); background: var(--accent-bg); }

/* ── Main content ────────────────────────────── */

main {
  flex: 1;
  padding: 2.5rem 3rem;
  min-width: 0;
  max-width: 760px;
}

main h1 { font-size: 1.75rem;  font-weight: 700; letter-spacing: -0.03em; margin-bottom: 1rem; }
main h2 { font-size: 1.25rem;  font-weight: 600; margin: 2rem 0 0.6rem; }
main h3 { font-size: 1.05rem;  font-weight: 600; margin: 1.5rem 0 0.4rem; }
main h4 { font-size: 0.95rem;  font-weight: 600; margin: 1.25rem 0 0.3rem; }

main p             { margin-bottom: 1rem; }
main ul, main ol   { margin: 0 0 1rem 1.4rem; }
main li            { margin-bottom: 0.2rem; }

main a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

main a:hover { text-decoration: none; }

main hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2rem 0;
}

main blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.5rem 1rem;
  margin: 0 0 1rem;
  color: var(--muted);
  background: var(--code-bg);
  border-radius: 0 4px 4px 0;
}

/* ── Code ─────────────────────────────────────── */

main code {
  font-family: "JetBrains Mono", "Fira Code", "Cascadia Code", "Menlo", monospace;
  font-size: 0.85em;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.1em 0.4em;
}

main pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.25rem;
  overflow-x: auto;
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

main pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.875rem;
}

/* ── Tables ──────────────────────────────────── */

main table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}

main th, main td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

main th { background: var(--code-bg); font-weight: 600; }

/* ── Home: block cards ───────────────────────── */

.blocks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.block-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  transition: border-color 0.15s ease;
}

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

.block-card h3 { font-size: 1rem; margin-bottom: 0.3rem; }
.block-card p  { margin: 0; font-size: 0.875rem; color: var(--muted); }

/* ── Block index: page list ──────────────────── */

.block-desc { color: var(--muted); margin-bottom: 1.5rem; }

.page-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
}

.page-list li a {
  display: block;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--accent);
  text-decoration: none;
  font-size: 0.95rem;
}

.page-list li:first-child a { border-top: 1px solid var(--border); }
.page-list li a:hover { color: var(--text); }

/* ── Responsive ──────────────────────────────── */

@media (max-width: 640px) {
  .sidebar { display: none; }
  main     { padding: 1.5rem; }
}