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

:root {
  --font-body: Georgia, 'Times New Roman', serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, Consolas, monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --ink: #1a1a1a;
  --ink-light: #444;
  --ink-muted: #666;
  --rule: #d4d0c8;
  --bg: #fafaf7;
  --accent: #2c2c2c;
}

html { background: var(--bg); }

body {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--bg);
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 32px 96px;
}

a { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
a:hover { color: #000; }

.book-header {
  text-align: center;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 32px;
  margin-bottom: 32px;
}

.book-header h1 {
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 12px;
}

.book-header .subtitle {
  font-size: 18px;
  color: var(--ink-light);
  margin-bottom: 16px;
}

.book-header .meta {
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--ink-muted);
  letter-spacing: 0.02em;
  margin-top: 8px;
}

.toc {
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 24px 28px;
  margin-bottom: 40px;
}

.toc h2 {
  font-family: var(--font-sans);
  font-size: 13px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 14px;
  font-weight: 600;
}

.toc ol {
  list-style: none;
  counter-reset: toc;
  padding-left: 0;
}

.toc li {
  counter-increment: toc;
  padding: 4px 0;
  font-size: 16px;
  border-bottom: 1px dotted var(--rule);
}

.toc li:last-child { border-bottom: none; }

.toc li::before {
  content: counter(toc, decimal-leading-zero) ".  ";
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-muted);
  margin-right: 8px;
}

.book-body { font-size: 17px; }

.book-body h2 {
  font-family: var(--font-sans);
  font-size: 22px;
  font-weight: 600;
  margin-top: 48px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 8px;
}

.book-body p { margin-bottom: 16px; }

.book-body .notice {
  background: #f3efe5;
  border-left: 3px solid var(--rule);
  padding: 14px 18px;
  font-size: 15px;
  color: var(--ink-light);
  margin-bottom: 20px;
}

.book-body pre {
  font-family: var(--font-mono);
  background: #fff;
  border: 1px solid var(--rule);
  padding: 20px 22px;
  white-space: pre-wrap;
  word-wrap: break-word;
  font-size: 14px;
  line-height: 1.65;
  margin: 16px 0 24px;
}

.chapter-list {
  list-style: none;
  padding-left: 0;
}

.chapter-list li {
  padding: 8px 0;
  border-bottom: 1px dotted var(--rule);
  font-size: 16px;
}

.chapter-list li:last-child { border-bottom: none; }

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: rgba(0,0,0,0.04);
  padding: 1px 5px;
  border-radius: 3px;
}

.book-footer {
  margin-top: 64px;
  padding-top: 24px;
  border-top: 1px solid var(--rule);
  text-align: center;
  font-family: var(--font-sans);
  font-size: 13px;
  color: var(--ink-muted);
}

.book-footer p { margin: 0; }