:root {
  --bg: #fafaf7;
  --text: #1a1a1a;
  --muted: #555;
  --accent: #003366;
  --accent-light: #1f4e79;
  --rule: #d0d0d0;
  --code-bg: #f4f4f4;
  --callout-bg: #fff8e1;
  --callout-border: #d4a017;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: Georgia, 'Times New Roman', serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  font-size: 17px;
}
a { color: var(--accent); text-decoration: none; border-bottom: 1px solid transparent; }
a:hover { border-bottom-color: var(--accent); }
strong { color: var(--accent); }
em { color: var(--muted); }
code { background: var(--code-bg); padding: 2px 5px; border-radius: 3px; font-family: 'SF Mono', Consolas, monospace; font-size: 0.9em; }
pre { background: var(--code-bg); padding: 1em; border-radius: 5px; overflow-x: auto; font-size: 0.85em; line-height: 1.45; border-left: 3px solid var(--accent); }
pre code { background: transparent; padding: 0; }
blockquote {
  border-left: 4px solid var(--accent-light);
  padding: 0.5em 1em;
  margin: 1.2em 0;
  background: #f0f5fa;
  font-style: italic;
  color: #2c3e50;
}
hr { border: 0; border-top: 1px solid var(--rule); margin: 2.5em 0; }

/* Layout */
header.site {
  background: linear-gradient(135deg, #003366 0%, #1f4e79 100%);
  color: #fff;
  padding: 1.5rem 2rem;
  border-bottom: 4px solid #d4a017;
}
header.site a { color: #fff; border-bottom-color: rgba(255,255,255,0.3); }
header.site .container { max-width: 1100px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; }
header.site h1 { margin: 0; font-size: 1.4rem; font-weight: normal; }
header.site nav { display: flex; gap: 1.2rem; flex-wrap: wrap; font-size: 0.95rem; }
header.site nav a { opacity: 0.9; }
header.site nav a:hover { opacity: 1; }

main { max-width: 820px; margin: 2.5rem auto; padding: 0 1.5rem; }
main h1 { font-size: 2rem; color: var(--accent); border-bottom: 2px solid var(--accent); padding-bottom: 0.4em; margin-bottom: 0.6em; }
main h2 { font-size: 1.4rem; color: var(--accent); margin-top: 2em; }
main h3 { font-size: 1.15rem; color: var(--accent-light); margin-top: 1.4em; }
main p { margin: 0.9em 0; text-align: justify; hyphens: auto; }
main ul, main ol { margin: 0.8em 0; padding-left: 1.5em; }
main li { margin: 0.4em 0; }

/* Landing page styles */
.landing-hero { text-align: center; padding: 2rem 0; }
.landing-hero h1 { font-size: 2.4rem; border-bottom: none; }
.landing-hero .subtitle { color: var(--muted); font-size: 1.1rem; font-style: italic; margin-bottom: 1rem; }
.landing-hero .meta { color: var(--muted); font-size: 0.95rem; margin-bottom: 2rem; }
.landing-hero .description { max-width: 700px; margin: 0 auto; text-align: left; }

.toc-list { list-style: none; padding: 0; margin: 2rem 0; }
.toc-list li { margin: 1.2em 0; padding: 1em 1.2em; background: #fff; border-left: 4px solid var(--accent-light); border-radius: 0 5px 5px 0; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.toc-list li .label { color: var(--muted); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.05em; display: block; margin-bottom: 0.3em; }
.toc-list li h2 { margin: 0 0 0.4em 0; font-size: 1.25rem; border-bottom: none; padding: 0; }
.toc-list li h2 a { color: var(--accent); }
.toc-list li p { margin: 0.3em 0; color: var(--muted); font-size: 0.95em; }

.callout {
  background: var(--callout-bg);
  border-left: 4px solid var(--callout-border);
  padding: 1em 1.2em;
  margin: 1.5em 0;
  border-radius: 0 5px 5px 0;
}
.callout strong { color: #8b6914; }

.download-box {
  background: #e8f0fa;
  border: 1px solid #b8d0e8;
  padding: 1.5em;
  border-radius: 8px;
  text-align: center;
  margin: 2em 0;
}
.download-box a {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 0.6em 1.5em;
  border-radius: 5px;
  font-weight: bold;
  border-bottom: none;
}
.download-box a:hover { background: var(--accent-light); }

footer.site {
  max-width: 820px;
  margin: 3rem auto 2rem;
  padding: 1.5rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
}
.chapter-nav { display: flex; justify-content: space-between; margin: 2.5em 0 1em; padding: 1em 0; border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.chapter-nav a { padding: 0.5em 1em; background: #fff; border-radius: 5px; border: 1px solid var(--rule); }
.chapter-nav .prev { margin-right: auto; }
.chapter-nav .next { margin-left: auto; }
.chapter-nav .home { margin: 0 auto; }

/* Print styles */
@media print {
  header.site, footer.site, .chapter-nav, .download-box, .no-print { display: none !important; }
  main { max-width: 100%; margin: 0; padding: 0; font-size: 11pt; }
  main h1 { page-break-before: avoid; }
  main h2 { page-break-after: avoid; }
  pre { background: #f4f4f4 !important; border: 1px solid #ccc; }
  a { color: #000; border-bottom: none; }
  a[href^="http"]:after { content: " (" attr(href) ")"; font-size: 0.85em; color: #555; }
}

/* Mobile */
@media (max-width: 600px) {
  body { font-size: 16px; }
  main h1 { font-size: 1.6rem; }
  header.site { padding: 1rem; }
  header.site h1 { font-size: 1.15rem; }
}