/* ============================================================
   CTinFold, Papers · shared spine
   Antique old-gold on warm paper. Ink-graphite for solids.
   Linked by every paper in the series.
   ============================================================ */
*, *::before, *::after { box-sizing:border-box; margin:0; padding:0; }
:root{
  --bg:#f4f1e9; --bg2:#efeadf; --bg3:#e9e3d5;
  --ink:#1b1813; --text:#2c2720; --muted:#6a6155; --muted2:#9a9081;
  --border:rgba(28,24,18,0.14); --border-gold:rgba(154,123,63,0.40);
  --gold:#9a7b3f; --gold-light:#b6924c; --gold-dim:#7c6536;
  --paper:#f6f3ec; --btn:#26211a; --btn-light:#3a3327;
  --ok:#4f6f47; --stop:#9a4a3f;
  --font-serif:'Libre Caslon Text',Georgia,'Times New Roman',serif;
  --font-display:'Libre Caslon Display','Libre Caslon Text',Georgia,serif;
  --font-mono:'IBM Plex Mono','Courier New',monospace;
  --font-sans:'IBM Plex Sans',system-ui,sans-serif;
}
html{scroll-behavior:smooth}
body{
  background:var(--bg);color:var(--text);font-family:var(--font-sans);
  font-weight:400;line-height:1.8;font-size:17px;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
::selection{background:rgba(154,123,63,0.22)}
::-webkit-scrollbar{width:3px}
::-webkit-scrollbar-track{background:var(--bg)}
::-webkit-scrollbar-thumb{background:var(--gold-dim)}

body::before{
  content:'';position:fixed;inset:0;pointer-events:none;z-index:9999;
  opacity:0.5;mix-blend-mode:multiply;
  background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
}

/* ---- rail ---- */
.rail{
  position:sticky;top:0;z-index:50;
  background:rgba(244,241,233,0.92);backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 48px;font-family:var(--font-mono);font-size:11px;letter-spacing:0.14em;
}
.rail a{color:var(--gold);text-decoration:none;font-weight:500}
.rail a:hover{color:var(--gold-dim)}
.rail .crumbs{color:var(--muted2)}
.rail .crumbs b{color:var(--gold);font-weight:500}

.paper{max-width:940px;margin:0 auto;padding:80px 56px 64px;position:relative}

/* ---- masthead ---- */
.masthead{
  display:grid;grid-template-columns:1fr auto;align-items:end;
  padding-bottom:26px;border-bottom:1px solid var(--border);margin-bottom:60px;gap:24px;
}
.masthead .logo{font-family:var(--font-mono);font-size:14px;letter-spacing:0.18em;color:var(--gold);margin-bottom:6px}
.masthead .pub{font-family:var(--font-mono);font-size:10px;letter-spacing:0.22em;color:var(--muted);text-transform:uppercase}
.masthead .right{text-align:right;font-family:var(--font-mono);font-size:10px;letter-spacing:0.14em;color:var(--muted);line-height:1.9;text-transform:uppercase}
.masthead .right .dot{display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--gold);margin-right:8px;vertical-align:1px;box-shadow:0 0 0 3px rgba(154,123,63,0.18)}

/* ---- head ---- */
.eyebrow{font-family:var(--font-mono);font-size:11px;letter-spacing:0.22em;text-transform:uppercase;color:var(--gold);margin-bottom:24px;display:flex;align-items:center;gap:14px}
.eyebrow::before{content:'';display:block;width:28px;height:1px;background:var(--gold)}
h1.title{font-family:var(--font-display);font-weight:400;font-size:clamp(40px,5.6vw,74px);line-height:1.04;letter-spacing:-0.01em;color:var(--ink);margin-bottom:24px;text-wrap:balance}
h1.title em{font-style:italic;color:var(--gold)}
.subtitle{font-family:var(--font-serif);font-style:italic;font-size:clamp(17px,2vw,21px);line-height:1.6;color:var(--muted);max-width:680px;margin-bottom:48px;text-wrap:pretty}

.abstract{border:1px solid var(--border-gold);background:var(--bg2);padding:30px 36px;margin-bottom:64px}
.abstract .lab{font-family:var(--font-mono);font-size:10px;letter-spacing:0.22em;text-transform:uppercase;color:var(--gold);margin-bottom:12px}
.abstract p{font-size:16px;line-height:1.85;color:var(--text)}

/* ---- chapters ---- */
.chapter{margin-bottom:64px}
.sec-num{font-family:var(--font-mono);font-size:12px;letter-spacing:0.18em;color:var(--gold);margin-bottom:14px}
.sec-title{font-family:var(--font-display);font-weight:400;font-size:clamp(26px,3.2vw,38px);line-height:1.12;color:var(--ink);margin-bottom:24px;text-wrap:balance}
.sec-title em{font-style:italic;color:var(--gold)}
.chapter p{margin-bottom:20px;color:var(--text);max-width:720px}
.chapter p .em{font-style:italic;color:var(--ink)}
.chapter p b{color:var(--ink);font-weight:600}

.pull{font-family:var(--font-display);font-weight:400;font-size:clamp(20px,2.6vw,28px);line-height:1.4;color:var(--ink);border-left:2px solid var(--gold);padding:6px 0 6px 28px;margin:36px 0;max-width:760px;text-wrap:balance}
.pull em{font-style:italic;color:var(--gold)}

/* ---- hash panel ---- */
.hash-panel{border:1px solid var(--border-gold);background:var(--bg2);padding:32px 36px;margin:40px 0;display:grid;grid-template-columns:auto 1fr;gap:32px;align-items:center}
.hash-panel .icon{font-family:var(--font-mono);font-size:42px;color:var(--border-gold);line-height:1;user-select:none}
.hash-panel .lab{font-family:var(--font-mono);font-size:10px;letter-spacing:0.22em;text-transform:uppercase;color:var(--gold);margin-bottom:10px}
.hash-panel .val{font-family:var(--font-mono);font-size:14px;color:var(--gold-dim);word-break:break-all;line-height:1.7;letter-spacing:0.04em}

/* ---- export-hash footer (shared DNA) ---- */
.exporthash{border-top:1px solid var(--border-gold);border-bottom:1px solid var(--border-gold);background:var(--bg3);margin:72px 0 0;padding:26px 36px;display:grid;grid-template-columns:auto 1fr auto;gap:28px;align-items:center}
.exporthash .lab{font-family:var(--font-mono);font-size:9px;letter-spacing:0.22em;text-transform:uppercase;color:var(--gold)}
.exporthash .hh{font-family:var(--font-mono);font-size:12px;color:var(--gold-dim);word-break:break-all;line-height:1.6;letter-spacing:0.03em}
.exporthash .note{font-family:var(--font-mono);font-size:9.5px;letter-spacing:0.1em;color:var(--muted);text-align:right;text-transform:uppercase;line-height:1.7}

/* ---- series nav ---- */
.series{margin-top:56px;display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--border);border:1px solid var(--border)}
.series a{background:var(--bg2);padding:24px 26px;text-decoration:none;display:flex;flex-direction:column;gap:8px;transition:background 0.25s}
.series a:hover{background:var(--bg3)}
.series .num{font-family:var(--font-mono);font-size:10px;letter-spacing:0.18em;color:var(--gold-dim)}
.series .nm{font-family:var(--font-serif);font-size:17px;color:var(--ink);line-height:1.3}
.series .go{font-family:var(--font-mono);font-size:10px;letter-spacing:0.12em;color:var(--gold);text-transform:uppercase;margin-top:4px}
.series a[aria-current] .go{color:var(--muted2)}

/* ---- colophon ---- */
.colophon{margin-top:64px;padding-top:32px;border-top:1px solid var(--border);display:grid;grid-template-columns:1fr 1fr;gap:32px;font-family:var(--font-mono);font-size:10.5px;letter-spacing:0.12em;color:var(--muted2);text-transform:uppercase;line-height:2}
.colophon b{color:var(--gold-dim);font-weight:500}
.colophon .right{text-align:right}

@media (max-width:920px){ .series{grid-template-columns:1fr} }
@media (max-width:820px){
  .paper{padding:48px 24px 64px}
  .rail{padding:12px 22px;font-size:10px}
  .masthead{grid-template-columns:1fr}
  .masthead .right{text-align:left}
  .hash-panel{grid-template-columns:1fr;gap:18px;padding:24px}
  .exporthash{grid-template-columns:1fr;gap:14px}
  .exporthash .note{text-align:left}
  .colophon{grid-template-columns:1fr}
  .colophon .right{text-align:left}
}