:root {
  --paper: #f4efe3;
  --paper-deep: #ece5d3;
  --ink: #1d1a14;
  --ink-soft: #4a443a;
  --oxblood: #7c1f1f;
  --oxblood-bright: #9e2b25;
  --gold: #9c7c2e;
  --rule: #c9bda0;
  --rule-strong: #a89a78;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: 'EB Garamond', serif;
  font-size: 19px;
  line-height: 1.65;
  position: relative;
  overflow-x: hidden;
}
/* paper grain */
body::before {
  content: '';
  position: fixed; inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 240 240' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.05'/%3E%3C/svg%3E");
  pointer-events: none; z-index: 50;
}
/* ledger rules running behind everything */
.ruled {
  background-image: repeating-linear-gradient(
    to bottom, transparent 0, transparent 31px, rgba(124,31,31,0.07) 31px, rgba(124,31,31,0.07) 32px
  );
}
.sheet {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 32px;
}
/* ============ banknote frame ============ */
.frame {
  position: fixed; inset: 10px;
  border: 1px solid var(--rule-strong);
  outline: 3px double var(--rule-strong);
  outline-offset: 3px;
  pointer-events: none; z-index: 40;
}
.frame::before, .frame::after {
  content: '✦';
  position: absolute; font-size: 11px; color: var(--gold);
}
.frame::before { top: -7px; left: 18px; }
.frame::after { bottom: -7px; right: 18px; }

/* ============ masthead ============ */
header {
  text-align: center;
  padding: 88px 24px 56px;
  position: relative;
}
.house {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px;
  letter-spacing: 0.42em;
  text-transform: uppercase;
  color: var(--oxblood);
  animation: rise 0.9s ease-out both;
}
.house::before, .house::after { content: ' — '; color: var(--gold); }
h1 {
  font-family: 'Fraunces', serif;
  font-optical-sizing: auto;
  font-weight: 900;
  font-size: clamp(56px, 11vw, 124px);
  line-height: 0.95;
  letter-spacing: -0.015em;
  margin: 26px 0 10px;
  animation: rise 0.9s 0.15s ease-out both;
}
h1 .drop { color: var(--oxblood); }
.tagline {
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 400;
  font-size: clamp(20px, 3vw, 28px);
  color: var(--ink-soft);
  animation: rise 0.9s 0.3s ease-out both;
}
.expedition {
  margin-top: 34px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12.5px;
  color: var(--ink-soft);
  letter-spacing: 0.12em;
  animation: rise 0.9s 0.45s ease-out both;
}
.expedition a { color: var(--oxblood); text-decoration: none; border-bottom: 1px solid var(--rule-strong); }
.expedition a:hover { border-bottom-color: var(--oxblood); }
@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}
/* engraved divider */
.divider {
  display: flex; align-items: center; gap: 14px;
  margin: 8px auto 0; max-width: 520px;
  animation: rise 0.9s 0.5s ease-out both;
}
.divider::before, .divider::after {
  content: ''; flex: 1; height: 1px;
  background: linear-gradient(to right, transparent, var(--rule-strong), transparent);
}
.divider span { font-size: 13px; color: var(--gold); }

/* ============ epigraph ============ */
.epigraph {
  max-width: 560px; margin: 30px auto 0;
  text-align: center; font-style: italic;
  font-size: 21px; color: var(--ink-soft);
  animation: rise 0.9s 0.6s ease-out both;
}
.epigraph cite {
  display: block; margin-top: 10px;
  font-family: 'IBM Plex Mono', monospace;
  font-style: normal; font-size: 12px;
  letter-spacing: 0.18em; text-transform: uppercase;
}

/* ============ sections ============ */
section { padding: 64px 0; position: relative; }
.section-no {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: 0.34em;
  text-transform: uppercase; color: var(--oxblood);
  margin-bottom: 14px;
}
.section-no::after { content: ' ·············'; color: var(--rule-strong); letter-spacing: 0; }
h2 {
  font-family: 'Fraunces', serif;
  font-weight: 600; font-size: clamp(32px, 5vw, 46px);
  line-height: 1.1; margin-bottom: 26px; letter-spacing: -0.01em;
}
p + p { margin-top: 1em; }
.lede { font-size: 22px; }
.lede::first-letter {
  font-family: 'Fraunces', serif;
  font-weight: 900; font-size: 64px;
  float: left; line-height: 0.85;
  padding: 4px 10px 0 0; color: var(--oxblood);
}
em.term { font-style: italic; color: var(--oxblood); }

/* ============ claim block ============ */
.claim {
  margin: 44px 0;
  padding: 38px 40px;
  border-top: 3px double var(--ink);
  border-bottom: 3px double var(--ink);
  text-align: center;
  font-family: 'Fraunces', serif;
  font-size: clamp(24px, 3.6vw, 33px);
  font-weight: 600; line-height: 1.35;
  background: var(--paper-deep);
}
.claim .red { color: var(--oxblood); font-style: italic; }

/* ============ postulate folios ============ */
.folio {
  display: grid;
  grid-template-columns: 86px 1fr;
  gap: 26px;
  padding: 34px 0;
  border-bottom: 1px solid var(--rule);
  opacity: 0; transform: translateY(18px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.folio.lit { opacity: 1; transform: none; }
.folio:last-of-type { border-bottom: none; }
.folio-num {
  font-family: 'Fraunces', serif;
  font-weight: 900; font-size: 58px; line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.4px var(--oxblood);
  text-align: right;
}
.folio h3 {
  font-family: 'Fraunces', serif;
  font-weight: 600; font-size: 25px;
  margin-bottom: 8px;
}
.folio h3 .label {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 500; font-size: 11.5px;
  letter-spacing: 0.26em; text-transform: uppercase;
  color: var(--gold); display: block; margin-bottom: 6px;
}
.folio p { font-size: 18.5px; color: var(--ink-soft); }
.folio .eq { margin-top: 14px; }

/* ============ equations ============ */
.eq {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 17px;
  background: var(--paper-deep);
  border: 1px solid var(--rule);
  border-left: 4px solid var(--oxblood);
  padding: 14px 20px;
  display: inline-block;
  color: var(--ink);
}
.eq i { font-style: italic; font-family: 'EB Garamond', serif; font-size: 19px; }
.eq-grand {
  display: block; text-align: center;
  font-size: clamp(19px, 3vw, 26px);
  padding: 30px 24px;
  margin: 34px 0;
  border: 1px solid var(--rule-strong);
  outline: 4px double var(--rule-strong);
  outline-offset: 5px;
  background: var(--paper-deep);
  position: relative;
}
.eq-grand .caption {
  display: block; margin-top: 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11.5px; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--oxblood);
}

/* ============ double-entry table ============ */
.book {
  width: 100%;
  border-collapse: collapse;
  margin: 36px 0 10px;
  font-size: 18px;
}
.book caption {
  caption-side: top; text-align: left;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: 0.3em;
  text-transform: uppercase; color: var(--ink-soft);
  padding-bottom: 12px;
}
.book th {
  font-family: 'Fraunces', serif;
  font-weight: 600; font-size: 16px;
  letter-spacing: 0.08em; text-transform: uppercase;
  text-align: left;
  border-top: 3px double var(--ink);
  border-bottom: 1px solid var(--ink);
  padding: 12px 14px;
}
.book th.debit, .book td.debit { color: var(--oxblood); }
.book td {
  padding: 13px 14px;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}
.book td:first-child {
  font-family: 'Fraunces', serif;
  font-weight: 600; font-size: 17px;
  width: 26%;
}
.book tr:hover td { background: rgba(124,31,31,0.045); }
.book tfoot td {
  border-top: 1px solid var(--ink);
  border-bottom: 3px double var(--ink);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 14px; letter-spacing: 0.06em;
}

/* ============ the invoice ============ */
.invoice-wrap { display: flex; justify-content: center; margin: 46px 0 18px; }
.invoice {
  width: min(620px, 100%);
  background: #fbf8ef;
  border: 1px solid var(--rule-strong);
  box-shadow: 6px 8px 0 rgba(29,26,20,0.12);
  padding: 36px 38px 30px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 14.5px;
  position: relative;
  transform: rotate(-0.6deg);
}
.invoice::before {
  content: '';
  position: absolute; top: -1px; left: 0; right: 0; height: 7px;
  background-image: linear-gradient(135deg, var(--paper) 5px, transparent 0), linear-gradient(225deg, var(--paper) 5px, transparent 0);
  background-size: 12px 12px; background-repeat: repeat-x;
}
.invoice h4 {
  font-size: 13px; letter-spacing: 0.32em; text-transform: uppercase;
  text-align: center; margin-bottom: 4px; color: var(--ink);
}
.invoice .sub {
  text-align: center; font-size: 11px; color: var(--ink-soft);
  letter-spacing: 0.14em; margin-bottom: 22px;
}
.invoice .row {
  display: flex; justify-content: space-between; gap: 18px;
  padding: 9px 0; border-bottom: 1px dotted var(--rule-strong);
}
.invoice .row span:last-child { text-align: right; white-space: nowrap; }
.invoice .row.total {
  border-bottom: none; border-top: 2px solid var(--ink);
  margin-top: 10px; padding-top: 14px;
  font-weight: 600;
}
.invoice .row.total span:last-child { color: var(--oxblood); }
.invoice .fine {
  margin-top: 20px; font-size: 11px; line-height: 1.7; color: var(--ink-soft);
}
/* wax stamp */
.stamp {
  position: absolute; right: -26px; bottom: -30px;
  width: 130px; height: 130px;
  border-radius: 50%;
  border: 2.5px solid var(--oxblood);
  display: grid; place-items: center;
  transform: rotate(12deg);
  color: var(--oxblood);
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px; letter-spacing: 0.2em; text-transform: uppercase;
  text-align: center; line-height: 1.5;
  background: radial-gradient(circle, rgba(158,43,37,0.08), transparent 70%);
  opacity: 0.92;
}
.stamp::before {
  content: ''; position: absolute; inset: 7px;
  border-radius: 50%; border: 1px solid var(--oxblood);
}

/* ============ discrimination table ============ */
.verdict { margin-top: 30px; }
.verdict .vrow {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0;
  border-bottom: 1px solid var(--rule);
}
.verdict .vrow:first-child { border-top: 3px double var(--ink); }
.verdict .vrow:last-child { border-bottom: 3px double var(--ink); }
.verdict .cell { padding: 16px 18px; font-size: 18px; }
.verdict .cell.who {
  font-family: 'Fraunces', serif; font-weight: 600;
  border-right: 1px solid var(--rule);
}
.verdict .cell.who small {
  display: block; font-family: 'IBM Plex Mono', monospace;
  font-weight: 400; font-size: 11px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--ink-soft); margin-top: 3px;
}
.verdict .us { background: rgba(124,31,31,0.06); }
.verdict .us .cell.who { color: var(--oxblood); }

/* ============ honesty / auditor's note ============ */
.auditor {
  border: 1px solid var(--rule-strong);
  padding: 30px 34px;
  background: var(--paper-deep);
  position: relative;
  margin-top: 36px;
}
.auditor::before {
  content: "AUDITOR'S NOTE";
  position: absolute; top: -10px; left: 24px;
  background: var(--paper-deep);
  padding: 0 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; letter-spacing: 0.3em; color: var(--oxblood);
}
.auditor ul { list-style: none; }
.auditor li {
  padding: 7px 0 7px 28px; position: relative;
  font-size: 17.5px; color: var(--ink-soft);
  border-bottom: 1px dotted var(--rule);
}
.auditor li:last-child { border-bottom: none; }
.auditor li::before {
  content: '✗'; position: absolute; left: 2px;
  color: var(--oxblood); font-weight: 600;
}
.auditor li.yes::before { content: '✓'; color: var(--gold); }

/* ============ footer ============ */
footer {
  text-align: center;
  padding: 70px 24px 90px;
}
footer .colophon {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--ink-soft);
  line-height: 2.2;
}
footer .motto {
  font-family: 'Fraunces', serif;
  font-style: italic; font-size: 24px;
  margin-bottom: 26px; color: var(--ink);
}
.sig {
  margin-top: 8px; font-size: 13px; color: var(--oxblood);
}

/* watermark Λ */
.watermark {
  position: fixed;
  right: -4vw; bottom: -10vh;
  font-family: 'Fraunces', serif;
  font-weight: 900;
  font-size: 56vh;
  color: rgba(124, 31, 31, 0.035);
  z-index: 0; pointer-events: none;
  line-height: 1;
}

@media (max-width: 640px) {
  body { font-size: 17px; }
  .folio { grid-template-columns: 1fr; gap: 8px; }
  .folio-num { text-align: left; font-size: 44px; }
  .verdict .vrow { grid-template-columns: 1fr; }
  .verdict .cell.who { border-right: none; border-bottom: 1px dotted var(--rule); }
  .stamp { right: -10px; bottom: -36px; width: 104px; height: 104px; }
  .frame { display: none; }
}

/* ============================================================
   FOLIO PAGES — shared components for Folios II, III, ...
   ============================================================ */
.folio-head { text-align: center; padding: 72px 24px 40px; }
.folio-head .house { animation: rise 0.9s ease-out both; }
.folio-head h1 {
  font-size: clamp(40px, 7.5vw, 78px);
  margin: 22px 0 8px;
}
.folio-head .tagline { font-size: clamp(18px, 2.6vw, 24px); }
.backbar {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 12px; letter-spacing: 0.18em; text-transform: uppercase;
  display: flex; justify-content: space-between; gap: 12px;
  max-width: 880px; margin: 0 auto; padding: 26px 32px 0;
}
.backbar a { color: var(--oxblood); text-decoration: none; border-bottom: 1px solid var(--rule-strong); }
.backbar a:hover { border-bottom-color: var(--oxblood); }

/* status stamps (inline) */
.tag {
  display: inline-block;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px; font-weight: 600;
  letter-spacing: 0.22em; text-transform: uppercase;
  padding: 3px 10px 2px;
  border: 1.5px solid; border-radius: 2px;
  vertical-align: middle;
  transform: rotate(-1deg);
}
.tag.theorem    { color: var(--gold); border-color: var(--gold); }
.tag.measured   { color: var(--oxblood); border-color: var(--oxblood); }
.tag.argued     { color: var(--ink-soft); border-color: var(--ink-soft); }
.tag.conjecture { color: var(--ink-soft); border-color: var(--ink-soft); border-style: dashed; }
.tag.open       { color: var(--ink-soft); border-color: var(--rule-strong); border-style: dotted; }
.tag.passed     { color: #2e5a2e; border-color: #2e5a2e; }

/* the kill-gate box */
.gate {
  border: 2px solid var(--oxblood);
  outline: 1px solid var(--oxblood);
  outline-offset: 4px;
  background: rgba(124, 31, 31, 0.05);
  padding: 26px 30px;
  margin: 34px 0;
  position: relative;
}
.gate::before {
  content: "KILL-GATE · WRITTEN BEFORE THE RUN";
  position: absolute; top: -10px; left: 22px;
  background: var(--paper);
  padding: 0 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px; letter-spacing: 0.26em; color: var(--oxblood);
}
.gate p { font-size: 18.5px; }

/* derivation steps */
.step {
  display: grid; grid-template-columns: 64px 1fr; gap: 22px;
  padding: 28px 0; border-bottom: 1px solid var(--rule);
}
.step:last-of-type { border-bottom: none; }
.step-num {
  font-family: 'Fraunces', serif; font-weight: 900;
  font-size: 40px; line-height: 1; text-align: right;
  color: transparent; -webkit-text-stroke: 1.2px var(--gold);
}
.step h3 { font-family: 'Fraunces', serif; font-weight: 600; font-size: 22px; margin-bottom: 6px; }
.step p { font-size: 18px; color: var(--ink-soft); }
.step .eq { margin-top: 12px; }

/* data tables (results) */
.data {
  width: 100%; border-collapse: collapse; margin: 28px 0;
  font-family: 'IBM Plex Mono', monospace; font-size: 14px;
}
.data caption {
  caption-side: top; text-align: left;
  font-size: 11.5px; letter-spacing: 0.28em; text-transform: uppercase;
  color: var(--ink-soft); padding-bottom: 10px;
}
.data th {
  border-top: 3px double var(--ink); border-bottom: 1px solid var(--ink);
  padding: 9px 10px; text-align: right; font-weight: 600; font-size: 12.5px;
  letter-spacing: 0.08em; text-transform: uppercase;
}
.data td { padding: 8px 10px; text-align: right; border-bottom: 1px solid var(--rule); }
.data th:first-child, .data td:first-child { text-align: left; }
.data tr.hi td { background: rgba(124,31,31,0.06); font-weight: 600; }
.data .neg { color: var(--oxblood); }

/* code / reproduction block */
.repro {
  font-family: 'IBM Plex Mono', monospace; font-size: 14px;
  background: var(--ink); color: var(--paper);
  padding: 18px 22px; margin: 26px 0;
  overflow-x: auto;
}
.repro .c { color: #b9ad8e; }
a.script {
  font-family: 'IBM Plex Mono', monospace; font-size: 13px;
  color: var(--oxblood); border-bottom: 1px solid var(--rule-strong);
  text-decoration: none;
}
a.script:hover { border-bottom-color: var(--oxblood); }

/* figure-ish callout */
.note {
  border-left: 4px solid var(--gold);
  background: var(--paper-deep);
  padding: 18px 24px; margin: 26px 0;
  font-size: 18px;
}
.note .label {
  font-family: 'IBM Plex Mono', monospace; font-size: 11px;
  letter-spacing: 0.26em; text-transform: uppercase; color: var(--gold);
  display: block; margin-bottom: 6px;
}

/* general ledger (index) rows */
.gl-row {
  display: grid; grid-template-columns: 96px 1fr auto; gap: 20px;
  align-items: baseline;
  padding: 22px 6px; border-bottom: 1px solid var(--rule);
  text-decoration: none; color: var(--ink);
}
.gl-row:hover { background: rgba(124,31,31,0.045); }
.gl-row .no { font-family: 'Fraunces', serif; font-weight: 900; font-size: 26px; color: var(--oxblood); }
.gl-row .what .t { font-family: 'Fraunces', serif; font-weight: 600; font-size: 22px; display: block; }
.gl-row .what .d { font-size: 16.5px; color: var(--ink-soft); }
.gl-row.dim { opacity: 0.55; }
@media (max-width: 640px) {
  .step { grid-template-columns: 1fr; gap: 6px; }
  .step-num { text-align: left; }
  .gl-row { grid-template-columns: 64px 1fr; }
  .gl-row .tag { grid-column: 2; justify-self: start; }
}