@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,600;0,8..60,700;1,8..60,400;1,8..60,600&family=Zilla+Slab:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root{
  --paper: #e9e5d9;
  --paper-deep: #ded8c7;
  --card: #f4f1e7;
  --ink: #201d18;
  --ink-soft: #4a453c;
  --ink-faint: #7c766a;
  --oxblood: #7a2020;
  --oxblood-deep: #591616;
  --navy: #24344a;
  --rule: #c9c2ab;
  --rule-strong: #a89f83;
  --stamp: #8a3a3a;
  --focus: #1c5b8f;
  --max: 780px;
}

*{ box-sizing: border-box; }

html{ scroll-behavior: smooth; }

body{
  margin: 0;
  background: var(--paper);
  background-image:
    radial-gradient(ellipse at top left, rgba(255,255,255,0.35), transparent 60%),
    repeating-linear-gradient(0deg, rgba(0,0,0,0.015) 0px, rgba(0,0,0,0.015) 1px, transparent 1px, transparent 3px);
  color: var(--ink);
  font-family: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a{ color: var(--oxblood); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover{ color: var(--oxblood-deep); }
a:focus-visible, button:focus-visible{ outline: 2px solid var(--focus); outline-offset: 2px; }

.label{
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-size: 11px;
  color: var(--ink-faint);
}

/* ---------- Top bar (chapter pages) ---------- */
.topbar{
  position: sticky; top: 0; z-index: 20;
  background: linear-gradient(var(--paper) 88%, transparent);
  padding: 14px 0 10px;
}
.topbar-inner{
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid var(--rule-strong);
  padding-bottom: 10px;
}
.topbar a.home-link{
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px; letter-spacing: 0.08em;
  color: var(--ink-soft); text-decoration: none;
  border: 1px solid var(--rule-strong);
  padding: 5px 10px; border-radius: 2px;
  background: var(--card);
}
.topbar a.home-link:hover{ border-color: var(--oxblood); color: var(--oxblood); }
.topbar .case-tag{
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px; color: var(--ink-faint); letter-spacing: 0.06em;
}

/* ---------- Wrapper ---------- */
.wrap{
  max-width: var(--max);
  margin: 0 auto;
  padding: 24px 24px 90px;
}

/* ---------- Index page ---------- */
.cover{
  padding: 64px 0 30px;
  text-align: center;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 10px;
}
.cover .stamp{
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px; letter-spacing: 0.22em;
  color: var(--stamp);
  border: 1.5px solid var(--stamp);
  padding: 5px 14px;
  border-radius: 2px;
  transform: rotate(-2deg);
  margin-bottom: 28px;
  opacity: 0.9;
}
.cover h1{
  font-family: 'Zilla Slab', Georgia, serif;
  font-weight: 700;
  font-size: 44px;
  line-height: 1.08;
  margin: 0 0 8px;
  letter-spacing: -0.01em;
}
.cover .ver{
  font-family: 'Zilla Slab', Georgia, serif;
  font-size: 21px;
  color: var(--ink-soft);
  margin: 0 0 4px;
}
.cover .meta{
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--ink-faint);
  margin-top: 10px;
}
.cover .epigraph{
  max-width: 480px;
  margin: 34px auto 0;
  font-style: italic;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.7;
}
.cover .epigraph cite{ display:block; font-style: normal; margin-top: 8px; font-size: 13px; color: var(--ink-faint); }

.intro-note{
  max-width: 600px;
  margin: 30px auto 0;
  font-size: 15px;
  color: var(--ink-soft);
  text-align: left;
  background: var(--card);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--oxblood);
  padding: 16px 20px;
  border-radius: 2px;
}

.file-index{ margin-top: 46px; }
.file-index > .label{ display:block; margin-bottom: 14px; }

.chapter-card{
  display: block;
  position: relative;
  border: 1px solid var(--rule-strong);
  background: var(--card);
  border-radius: 3px;
  padding: 18px 20px 18px 84px;
  margin-bottom: 14px;
  text-decoration: none;
  color: var(--ink);
  transition: transform .12s ease, box-shadow .12s ease, border-color .12s ease;
  box-shadow: 2px 2px 0 rgba(0,0,0,0.03);
}
.chapter-card:hover{
  transform: translateX(2px);
  border-color: var(--oxblood);
  box-shadow: 3px 3px 0 rgba(122,32,32,0.10);
}
.chapter-card .num{
  position: absolute;
  left: 18px; top: 50%; transform: translateY(-50%);
  font-family: 'JetBrains Mono', monospace;
  font-size: 26px; font-weight: 600;
  color: var(--rule-strong);
  width: 46px; text-align: center;
}
.chapter-card:hover .num{ color: var(--oxblood); }
.chapter-card .ctitle{
  font-family: 'Zilla Slab', Georgia, serif;
  font-weight: 600;
  font-size: 18px;
  margin: 0 0 4px;
}
.chapter-card .csub{
  font-size: 13px; color: var(--ink-faint);
  font-family: 'JetBrains Mono', monospace;
}

footer.site-footer{
  max-width: var(--max);
  margin: 60px auto 0;
  padding: 20px 24px 40px;
  text-align: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--ink-faint);
  border-top: 1px solid var(--rule);
}

/* ---------- Chapter page ---------- */
.chapter-head{
  padding: 26px 0 18px;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 28px;
}
.chapter-head .num-badge{
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--oxblood);
  border: 1px solid var(--oxblood);
  padding: 3px 9px;
  border-radius: 2px;
  margin-bottom: 12px;
}
.chapter-head h1{
  font-family: 'Zilla Slab', Georgia, serif;
  font-size: 32px;
  line-height: 1.15;
  margin: 0;
}

.on-page-toc{
  background: var(--card);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 16px 20px;
  margin-bottom: 36px;
}
.on-page-toc summary{
  cursor: pointer;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.on-page-toc ul{ list-style: none; margin: 14px 0 0; padding: 0; column-gap: 24px; }
.on-page-toc li{ margin: 4px 0; font-size: 14px; }
.on-page-toc li.lvl-3{ margin-left: 16px; font-size: 13px; }
.on-page-toc li.lvl-4{ margin-left: 32px; font-size: 12.5px; }
.on-page-toc a{ text-decoration: none; color: var(--ink-soft); }
.on-page-toc a:hover{ color: var(--oxblood); }

.section-block{ margin-bottom: 6px; scroll-margin-top: 76px; }

h2.h-lvl2, h3.h-lvl3, h4.h-lvl4{
  font-family: 'Zilla Slab', Georgia, serif;
  scroll-margin-top: 76px;
}
h2.h-lvl2{
  font-size: 24px; font-weight: 700;
  margin: 46px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--rule-strong);
  color: var(--ink);
}
h3.h-lvl3{
  font-size: 19px; font-weight: 600;
  margin: 34px 0 12px;
  color: var(--navy);
}
h4.h-lvl4{
  font-size: 15.5px; font-weight: 600; font-style: italic;
  margin: 26px 0 10px;
  color: var(--ink-soft);
}
.hnum{
  font-family: 'JetBrains Mono', monospace;
  font-weight: 500;
  color: var(--oxblood);
  margin-right: 10px;
  font-style: normal;
}
h2.h-lvl2 .hnum{ font-size: 18px; }
h3.h-lvl3 .hnum{ font-size: 15px; }
h4.h-lvl4 .hnum{ font-size: 12.5px; }

.perma{
  opacity: 0;
  margin-left: 8px;
  font-size: 0.7em;
  text-decoration: none;
  color: var(--ink-faint);
}
h2.h-lvl2:hover .perma, h3.h-lvl3:hover .perma, h4.h-lvl4:hover .perma{ opacity: 1; }

p.body-p{ margin: 0 0 14px; text-align: justify; hyphens: auto; }

p.question{
  font-family: 'Zilla Slab', Georgia, serif;
  font-style: italic;
  font-weight: 600;
  color: var(--oxblood);
  margin: 22px 0 8px;
  font-size: 16.5px;
}

ul.bullets{ margin: 0 0 16px; padding-left: 0; list-style: none; }
ul.bullets li{
  position: relative;
  padding-left: 20px;
  margin-bottom: 7px;
}
ul.bullets li::before{
  content: "\2014";
  position: absolute; left: 0; color: var(--oxblood);
}

.quote-block{
  margin: 14px 0 20px;
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--rule-strong);
  font-style: italic;
  color: var(--ink-soft);
  font-size: 15px;
}
.quote-block p{ margin: 2px 0; }

.chapter-nav{
  display: flex; justify-content: space-between; gap: 16px;
  margin-top: 60px; padding-top: 20px;
  border-top: 1px solid var(--rule-strong);
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
}
.chapter-nav a{ text-decoration: none; color: var(--ink-soft); }
.chapter-nav a:hover{ color: var(--oxblood); }
.chapter-nav .prev::before{ content: "\2190 "; }
.chapter-nav .next::after{ content: " \2192"; }
.chapter-nav .to-index{ color: var(--ink-faint); }

/* ---------- Back to top ---------- */
.top-link{
  position: fixed; right: 22px; bottom: 22px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  background: var(--card);
  border: 1px solid var(--rule-strong);
  color: var(--ink-soft);
  padding: 8px 10px;
  border-radius: 3px;
  text-decoration: none;
  box-shadow: 2px 2px 0 rgba(0,0,0,0.05);
}
.top-link:hover{ border-color: var(--oxblood); color: var(--oxblood); }

@media (max-width: 640px){
  .cover h1{ font-size: 30px; }
  .cover .ver{ font-size: 17px; }
  body{ font-size: 16px; }
  .chapter-card{ padding-left: 70px; }
  .chapter-head h1{ font-size: 25px; }
  h2.h-lvl2{ font-size: 20px; }
  .on-page-toc ul{ columns: 1; }
}

@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior: auto; }
  .chapter-card{ transition: none; }
}