:root {
  --bg: #fbf8f3;
  --fg: #1a1a1a;
  --muted: #555;
  --accent: #b7410e;
  --accent-soft: #f0d6c8;
  --border: #e0d8cb;
  --code-bg: #f3ede0;
  --max-width: 720px;
  --serif: Georgia, "Times New Roman", Times, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a1714;
    --fg: #e8e3da;
    --muted: #a9a298;
    --accent: #e8845c;
    --accent-soft: #3a2218;
    --border: #2e2a25;
    --code-bg: #25201b;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.65;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 12px 20px;
  font-family: var(--sans);
  font-size: 14px;
}

.topbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 24px;
}

.topbar a.brand {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
  letter-spacing: -0.01em;
}

.topbar nav {
  flex: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 13px;
}

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

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

.topbar input[type=search] {
  font-family: var(--sans);
  font-size: 13px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--fg);
  border-radius: 4px;
  width: 200px;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 20px 120px;
}

main.wide { max-width: 1000px; }

h1 {
  font-size: 36px;
  line-height: 1.2;
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 26px;
  line-height: 1.25;
  margin: 56px 0 16px;
  letter-spacing: -0.01em;
  border-bottom: 1px solid var(--border);
  padding-bottom: 6px;
}

h3 {
  font-size: 20px;
  line-height: 1.3;
  margin: 36px 0 12px;
}

h4 {
  font-size: 17px;
  margin: 28px 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  font-family: var(--sans);
}

p { margin: 0 0 16px; }

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover { text-decoration-thickness: 2px; }

blockquote {
  margin: 24px 0;
  padding: 4px 20px;
  border-left: 4px solid var(--accent);
  color: var(--muted);
  font-style: italic;
}

code, pre {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.9em;
  background: var(--code-bg);
}

code { padding: 1px 5px; border-radius: 3px; }

pre {
  padding: 14px 16px;
  overflow-x: auto;
  border-radius: 6px;
  line-height: 1.5;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-family: var(--sans);
  font-size: 15px;
}

th, td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

th { font-weight: 600; color: var(--muted); }

tr:hover td { background: var(--accent-soft); }

ul, ol { padding-left: 24px; margin: 16px 0; }
li { margin: 6px 0; }

.subtitle {
  font-family: var(--sans);
  color: var(--muted);
  font-size: 16px;
  margin-bottom: 32px;
}

.toc {
  background: var(--accent-soft);
  border-radius: 8px;
  padding: 18px 24px;
  margin: 28px 0;
  font-family: var(--sans);
  font-size: 15px;
}
.toc h4 { margin-top: 0; color: var(--accent); }

.section-list {
  list-style: none;
  padding: 0;
  margin: 32px 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

@media (min-width: 700px) {
  .section-list { grid-template-columns: 1fr 1fr; }
}

.section-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 18px;
  background: var(--bg);
  transition: border-color 0.2s, transform 0.1s;
}

.section-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.section-card a {
  text-decoration: none;
  color: var(--fg);
  display: block;
}

.section-card .num {
  font-family: var(--sans);
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.08em;
}

.section-card .title {
  font-size: 18px;
  margin: 4px 0 6px;
  letter-spacing: -0.01em;
}

.section-card .desc {
  font-family: var(--sans);
  font-size: 14px;
  color: var(--muted);
  line-height: 1.5;
}

.footer-nav {
  margin-top: 80px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-family: var(--sans);
  font-size: 14px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
}

.footer-nav a { color: var(--muted); }

.search-results {
  position: absolute;
  top: 50px;
  right: 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  width: 360px;
  max-height: 400px;
  overflow-y: auto;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  font-family: var(--sans);
  font-size: 14px;
  display: none;
}

.search-results.open { display: block; }

.search-results a {
  display: block;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
  color: var(--fg);
}

.search-results a:hover { background: var(--accent-soft); }

.search-results .hit-section {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.tldr {
  background: var(--code-bg);
  border-left: 4px solid var(--accent);
  padding: 16px 20px;
  margin: 24px 0;
  border-radius: 0 6px 6px 0;
}

.tldr h4 {
  margin-top: 0;
  color: var(--accent);
}

.caveat {
  background: var(--accent-soft);
  padding: 12px 16px;
  border-radius: 6px;
  margin: 20px 0;
  font-size: 15px;
  font-family: var(--sans);
}

.ref {
  font-size: 13px;
  color: var(--muted);
  font-family: var(--sans);
}

@media (max-width: 600px) {
  .topbar input[type=search] { display: none; }
  h1 { font-size: 28px; }
  h2 { font-size: 22px; }
  body { font-size: 17px; }
}