/* OHAO Engine — multi-page visual textbook */

:root {
  --ink: #0a0b0e;
  --ink-soft: #11141a;
  --paper: #171b24;
  --paper-lift: #1e2430;
  --rule: #2a3140;
  --rule-soft: #222833;
  --ivory: #ebe4d6;
  --ivory-dim: #a39c8e;
  --ivory-mute: #6e685c;
  --copper: #c9a27a;
  --copper-dim: #8a6f52;
  --ray: #6eb8d4;
  --ray-hot: #9ad4e8;
  --emerald: #7dba8a;
  --warn: #d4a05a;
  --danger: #c76b6b;

  --font-display: "Fraunces", "Iowan Old Style", Georgia, serif;
  --font-body: "Source Serif 4", "Charter", Georgia, serif;
  --font-sans: "DM Sans", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;

  --measure: 40rem;
  --page: min(820px, 92vw);
  --wide: min(1040px, 94vw);
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --toc-w: 240px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1 !important; transform: none !important; }
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--ivory);
  font-family: var(--font-body);
  font-size: clamp(1.05rem, 0.98rem + 0.3vw, 1.15rem);
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 9999;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' 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)'/%3E%3C/svg%3E");
}

::selection {
  background: color-mix(in srgb, var(--ray) 40%, transparent);
  color: #fff;
}

a { color: var(--ray-hot); text-decoration-thickness: 1px; text-underline-offset: 0.18em; }
a:hover { color: #fff; }

/* Progress */
.progress {
  position: fixed; top: 0; left: 0; height: 2px; width: 0%;
  background: linear-gradient(90deg, var(--copper), var(--ray));
  z-index: 200; pointer-events: none;
}

/* TOC */
.toc {
  position: fixed; top: 0; left: 0;
  width: var(--toc-w); height: 100vh;
  padding: 1.5rem 0.9rem 2rem;
  background: color-mix(in srgb, var(--ink) 94%, #000);
  border-right: 1px solid var(--rule-soft);
  overflow-y: auto; z-index: 50;
  display: flex; flex-direction: column; gap: 0.08rem;
}
.toc-brand {
  font-family: var(--font-sans); font-size: 0.68rem;
  letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--copper); margin-bottom: 0.25rem;
}
.toc-title {
  font-family: var(--font-display); font-size: 1rem; font-weight: 500;
  margin: 0 0 1.1rem; line-height: 1.25; color: var(--ivory);
}
.toc-title span {
  display: block; font-family: var(--font-sans); font-size: 0.68rem;
  font-weight: 400; letter-spacing: 0.04em; color: var(--ivory-mute);
  margin-top: 0.3rem; text-transform: uppercase;
}
.toc .group {
  font-family: var(--font-sans); font-size: 0.62rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--ivory-mute);
  padding: 0.75rem 0.5rem 0.25rem;
}
.toc a {
  display: block; font-family: var(--font-sans); font-size: 0.76rem;
  color: var(--ivory-mute); text-decoration: none;
  padding: 0.34rem 0.5rem; border-radius: 4px;
  border-left: 2px solid transparent; line-height: 1.35;
}
.toc a .num {
  color: var(--copper-dim); font-variant-numeric: tabular-nums;
  margin-right: 0.35rem; font-size: 0.7rem;
}
.toc a:hover { color: var(--ivory); background: var(--paper); }
.toc a.active {
  color: var(--ivory); border-left-color: var(--ray); background: var(--paper);
}
.toc-foot {
  margin-top: auto; padding-top: 1.2rem;
  font-family: var(--font-sans); font-size: 0.66rem;
  color: var(--ivory-mute); line-height: 1.5;
}
.toc-foot a { color: var(--copper); text-decoration: none; display: inline; padding: 0; border: 0; }

.book { margin-left: var(--toc-w); min-height: 100vh; }

/* Cover (home only) */
.cover {
  position: relative; min-height: 92vh;
  display: grid; align-items: end;
  padding: clamp(2rem, 5vw, 4rem) var(--gutter) clamp(2.5rem, 7vh, 4rem);
  overflow: hidden; background: #050608;
}
.cover-media { position: absolute; inset: 0; z-index: 0; }
.cover-media video, .cover-media img {
  width: 100%; height: 100%; object-fit: cover; object-position: center 40%;
  opacity: 0.52; filter: saturate(0.92) contrast(1.05);
}
.cover-media::after {
  content: ""; position: absolute; inset: 0;
  background:
    linear-gradient(180deg, rgba(5,6,8,0.3) 0%, rgba(5,6,8,0.12) 35%, rgba(5,6,8,0.78) 72%, rgba(5,6,8,0.97) 100%),
    linear-gradient(90deg, rgba(5,6,8,0.55) 0%, transparent 48%);
}
.cover-inner { position: relative; z-index: 1; max-width: 42rem; }
.cover-eyebrow {
  font-family: var(--font-sans); font-size: 0.7rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 1rem;
}
.cover h1 {
  font-family: var(--font-display); font-weight: 450;
  font-size: clamp(2.6rem, 6vw, 4.4rem); line-height: 1.02;
  letter-spacing: -0.02em; margin: 0 0 1rem; color: #f5f0e6;
}
.cover h1 em { font-style: italic; font-weight: 400; color: var(--ray-hot); }
.cover-lede {
  font-size: clamp(1.05rem, 1rem + 0.4vw, 1.28rem); line-height: 1.55;
  color: var(--ivory-dim); max-width: 34rem; margin: 0 0 1.5rem;
}
.cover-meta {
  display: flex; flex-wrap: wrap; gap: 0.45rem;
  font-family: var(--font-sans); font-size: 0.7rem;
  letter-spacing: 0.06em; text-transform: uppercase;
}
.cover-meta span {
  border: 1px solid var(--rule); color: var(--ivory-dim);
  padding: 0.32rem 0.6rem; border-radius: 999px;
  background: rgba(10,11,14,0.45);
}

/* Chapter page shell */
.page {
  max-width: var(--wide);
  margin: 0 auto;
  padding: clamp(2.5rem, 6vh, 4rem) var(--gutter) 5rem;
}
.page.narrow { max-width: calc(var(--page) + 2 * var(--gutter)); }

.chapter-head {
  display: grid; grid-template-columns: auto 1fr; gap: 1rem 1.3rem;
  align-items: end; margin-bottom: 2rem; padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--rule);
}
.chapter-num {
  font-family: var(--font-display); font-size: clamp(3.2rem, 7vw, 5rem);
  font-weight: 300; line-height: 0.85;
  color: color-mix(in srgb, var(--copper) 55%, transparent);
  letter-spacing: -0.04em;
}
.chapter-kicker {
  font-family: var(--font-sans); font-size: 0.68rem; letter-spacing: 0.2em;
  text-transform: uppercase; color: var(--copper); margin: 0 0 0.35rem;
}
.chapter-head h1 {
  font-family: var(--font-display); font-weight: 500;
  font-size: clamp(1.75rem, 3.2vw, 2.4rem); line-height: 1.12;
  letter-spacing: -0.015em; margin: 0; color: var(--ivory);
}

/* Breadcrumb / pager */
.crumb {
  font-family: var(--font-sans); font-size: 0.75rem; color: var(--ivory-mute);
  margin-bottom: 1.5rem;
}
.crumb a { color: var(--copper); text-decoration: none; }
.crumb a:hover { color: var(--ivory); }
.pager {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;
  margin-top: 3.5rem; padding-top: 1.5rem; border-top: 1px solid var(--rule);
}
.pager a {
  display: block; text-decoration: none; padding: 1rem 1.1rem;
  border: 1px solid var(--rule); border-radius: 2px; background: var(--paper);
  transition: border-color 0.15s;
}
.pager a:hover { border-color: var(--ray); }
.pager .label {
  font-family: var(--font-sans); font-size: 0.65rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--ivory-mute); margin-bottom: 0.3rem;
}
.pager .title {
  font-family: var(--font-display); font-size: 1.05rem; color: var(--ivory);
}
.pager .next { text-align: right; }

/* Prose */
.prose { max-width: var(--measure); }
.prose > p, .prose > ul, .prose > ol { color: var(--ivory-dim); }
.prose p { margin: 0 0 1.05rem; }
.prose p.lead {
  font-size: 1.18em; line-height: 1.55; color: var(--ivory); margin-bottom: 1.35rem;
}
.prose strong { color: var(--ivory); font-weight: 600; }
.prose h2 {
  font-family: var(--font-display); font-weight: 500; font-size: 1.55rem;
  margin: 2.6rem 0 0.85rem; color: var(--ivory); letter-spacing: -0.01em;
}
.prose h3 {
  font-family: var(--font-display); font-weight: 500; font-size: 1.2rem;
  margin: 2rem 0 0.65rem; color: var(--ivory);
}
.prose h4 {
  font-family: var(--font-sans); font-size: 0.78rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--copper); margin: 1.6rem 0 0.5rem;
}
.prose ul, .prose ol { margin: 0 0 1.15rem; padding-left: 1.25rem; }
.prose li { margin-bottom: 0.4rem; }
.prose li::marker { color: var(--copper-dim); }
.prose code {
  font-family: var(--font-mono); font-size: 0.86em; color: var(--ray-hot);
  background: var(--paper); padding: 0.1em 0.36em; border-radius: 4px;
  border: 1px solid var(--rule-soft);
}
.prose hr {
  border: 0; border-top: 1px solid var(--rule); margin: 2.5rem 0;
}

/* In-page mini TOC */
.on-this-page {
  max-width: var(--measure);
  margin: 0 0 2rem;
  padding: 1rem 1.15rem;
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: 2px;
}
.on-this-page .otp-label {
  font-family: var(--font-sans); font-size: 0.65rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 0.55rem;
}
.on-this-page ol {
  margin: 0; padding-left: 1.15rem;
  font-family: var(--font-sans); font-size: 0.88rem;
}
.on-this-page a { color: var(--ivory-dim); text-decoration: none; }
.on-this-page a:hover { color: var(--ray-hot); }

/* Asides */
.aside {
  max-width: var(--measure); margin: 1.5rem 0 1.7rem;
  padding: 1rem 1.15rem; border-left: 3px solid var(--copper);
  background: linear-gradient(90deg, var(--paper) 0%, transparent 100%);
}
.aside.ray { border-left-color: var(--ray); }
.aside.note { border-left-color: var(--emerald); }
.aside.warn { border-left-color: var(--warn); }
.aside-label {
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 0.3rem;
}
.aside.ray .aside-label { color: var(--ray); }
.aside.note .aside-label { color: var(--emerald); }
.aside.warn .aside-label { color: var(--warn); }
.aside p { margin: 0; color: var(--ivory-dim); font-size: 0.95em; }
.aside p + p { margin-top: 0.55rem; }

/* Design decision card */
.decision {
  max-width: var(--measure);
  margin: 1.4rem 0 1.8rem;
  border: 1px solid var(--rule);
  border-radius: 2px;
  overflow: hidden;
  background: var(--ink-soft);
}
.decision-head {
  display: flex; gap: 0.75rem; align-items: baseline;
  padding: 0.75rem 1.1rem;
  background: var(--paper);
  border-bottom: 1px solid var(--rule-soft);
}
.decision-tag {
  font-family: var(--font-sans); font-size: 0.62rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--ray); white-space: nowrap;
}
.decision-head h4 {
  margin: 0; font-family: var(--font-display); font-size: 1.05rem;
  font-weight: 500; color: var(--ivory); text-transform: none; letter-spacing: 0;
}
.decision-body { padding: 1rem 1.1rem 1.15rem; }
.decision-body p { margin: 0 0 0.65rem; color: var(--ivory-dim); font-size: 0.95rem; }
.decision-body p:last-child { margin-bottom: 0; }
.decision-body .why { color: var(--copper); font-family: var(--font-sans); font-size: 0.72rem; letter-spacing: 0.08em; text-transform: uppercase; }

/* Plates */
.plate { margin: 2.2rem 0 2.4rem; max-width: var(--wide); }
.plate-frame {
  background: var(--ink-soft); border: 1px solid var(--rule);
  border-radius: 2px; overflow: hidden;
}
.plate-frame img, .plate-frame video { display: block; width: 100%; height: auto; }
.plate-frame.svg-frame {
  padding: clamp(0.9rem, 2.5vw, 1.75rem);
  background: radial-gradient(ellipse at 30% 20%, rgba(110,184,212,0.06), transparent 55%), var(--paper);
  overflow: visible; /* do not clip tall workflow diagrams */
}
/* Full-width SVG diagrams — preserve viewBox aspect ratio; do not max-height clip */
.plate-frame svg,
.plate-frame.svg-frame svg {
  display: block;
  width: 100%;
  height: auto;
  max-height: none;
  overflow: visible;
}
/* External SVG/images used as plates */
.plate-frame img[src$=".svg"],
.plate.fullpage .plate-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-height: none;
}
.plate-cap {
  display: grid; grid-template-columns: auto 1fr; gap: 0.7rem 1rem;
  margin-top: 0.7rem; padding: 0 0.1rem;
}
.plate-id {
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--copper); white-space: nowrap; padding-top: 0.12rem;
}
.plate-cap p {
  margin: 0; font-family: var(--font-sans); font-size: 0.84rem;
  line-height: 1.5; color: var(--ivory-mute);
}
.plate-cap strong { color: var(--ivory-dim); font-weight: 500; }

/* Math */
.math-block {
  max-width: var(--measure);
  margin: 1.3rem 0 1.6rem;
  padding: 1.1rem 1.2rem;
  background: #0d1016;
  border: 1px solid var(--rule);
  border-radius: 2px;
  overflow-x: auto;
  text-align: center;
  color: var(--ivory);
}
.math-block .katex { font-size: 1.15em; }
.math-inline .katex { font-size: 1.02em; }
.math-note {
  max-width: var(--measure);
  font-family: var(--font-sans); font-size: 0.82rem;
  color: var(--ivory-mute); margin: -0.6rem 0 1.4rem; line-height: 1.45;
}

/* Tables */
.data-table {
  width: 100%; max-width: var(--wide);
  border-collapse: collapse; margin: 1.3rem 0 1.8rem;
  font-family: var(--font-sans); font-size: 0.86rem;
}
.data-table th {
  text-align: left; font-size: 0.66rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--ivory-mute); font-weight: 500;
  padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--rule);
}
.data-table td {
  padding: 0.65rem 0.7rem; border-bottom: 1px solid var(--rule-soft);
  color: var(--ivory-dim); vertical-align: top;
}
.data-table tr:hover td { background: var(--paper); }
.data-table code {
  font-family: var(--font-mono); font-size: 0.84em; color: var(--ray-hot);
}
.badge {
  display: inline-block; font-size: 0.66rem; letter-spacing: 0.08em;
  text-transform: uppercase; padding: 0.18rem 0.42rem; border-radius: 3px; border: 1px solid;
}
.badge.ok { color: var(--emerald); border-color: color-mix(in srgb, var(--emerald) 40%, transparent); }
.badge.soft { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 40%, transparent); }
.badge.exp { color: var(--ray); border-color: color-mix(in srgb, var(--ray) 40%, transparent); }

/* File map */
.file-map {
  max-width: var(--wide); margin: 1.2rem 0 1.8rem;
  border: 1px solid var(--rule); border-radius: 2px; overflow: hidden;
}
.file-map .row {
  display: grid; grid-template-columns: minmax(10rem, 0.9fr) 1.4fr;
  gap: 0.75rem; padding: 0.65rem 0.9rem;
  border-bottom: 1px solid var(--rule-soft);
  font-family: var(--font-sans); font-size: 0.84rem;
}
.file-map .row:last-child { border-bottom: 0; }
.file-map .row:nth-child(odd) { background: var(--paper); }
.file-map code { color: var(--ray-hot); font-family: var(--font-mono); font-size: 0.82em; }
.file-map .desc { color: var(--ivory-mute); }

/* Compare / cards */
.compare {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1rem;
  margin: 1.5rem 0 2rem; max-width: var(--wide);
}
.compare-card {
  background: var(--paper); border: 1px solid var(--rule);
  border-radius: 2px; padding: 1.1rem 1.2rem 1.2rem;
}
.compare-card h4 {
  font-family: var(--font-sans); font-size: 0.68rem; letter-spacing: 0.14em;
  text-transform: uppercase; margin: 0 0 0.45rem; color: var(--ray);
}
.compare-card.deferred h4 { color: var(--copper); }
.compare-card h3 {
  font-family: var(--font-display); font-size: 1.25rem; font-weight: 500;
  margin: 0 0 0.55rem; color: var(--ivory);
}
.compare-card p, .compare-card li { margin: 0; font-size: 0.92rem; color: var(--ivory-dim); line-height: 1.5; }
.compare-card ul { margin: 0.7rem 0 0; padding-left: 1.1rem; }
.compare-card li { margin-bottom: 0.28rem; }

/* Module catalog (home) */
.catalog {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 0.85rem; margin: 1.5rem 0 2.5rem;
}
.catalog a {
  display: block; text-decoration: none; padding: 1.15rem 1.2rem;
  background: var(--paper); border: 1px solid var(--rule); border-radius: 2px;
  transition: border-color 0.15s, transform 0.15s;
}
.catalog a:hover { border-color: var(--ray); transform: translateY(-1px); }
.catalog .num {
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 0.35rem;
}
.catalog h3 {
  font-family: var(--font-display); font-size: 1.2rem; font-weight: 500;
  margin: 0 0 0.4rem; color: var(--ivory);
}
.catalog p {
  margin: 0; font-family: var(--font-sans); font-size: 0.82rem;
  color: var(--ivory-mute); line-height: 1.45;
}

/* Listing */
.listing {
  margin: 1.3rem 0 1.7rem; border: 1px solid var(--rule); border-radius: 2px;
  overflow: hidden; background: #0d1016; max-width: var(--wide);
}
.listing-bar {
  display: flex; justify-content: space-between; padding: 0.42rem 0.85rem;
  background: var(--paper); border-bottom: 1px solid var(--rule-soft);
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--ivory-mute);
}
.listing pre {
  margin: 0; padding: 0.95rem 1.1rem; overflow-x: auto;
  font-family: var(--font-mono); font-size: 0.8rem; line-height: 1.55; color: var(--ivory-dim);
}
.listing .c { color: #6a7368; }
.listing .k { color: var(--ray); }
.listing .s { color: var(--copper); }
.listing .g { color: var(--emerald); }

/* Steps */
.steps {
  list-style: none; margin: 1.3rem 0 1.8rem; padding: 0; max-width: var(--measure);
  counter-reset: step;
}
.steps li {
  display: grid; grid-template-columns: 2.8rem 1fr; gap: 0.8rem;
  padding: 0.9rem 0; border-top: 1px solid var(--rule-soft); counter-increment: step;
}
.steps li:last-child { border-bottom: 1px solid var(--rule-soft); }
.steps .step-n {
  font-family: var(--font-display); font-size: 1.35rem; color: var(--copper-dim); line-height: 1;
}
.steps .step-n::before { content: counter(step, decimal-leading-zero); }
.steps h4 {
  font-family: var(--font-display); font-size: 1.05rem; font-weight: 500;
  margin: 0 0 0.25rem; color: var(--ivory); text-transform: none; letter-spacing: 0;
}
.steps p { margin: 0; color: var(--ivory-dim); font-size: 0.94rem; }

.spread {
  display: grid; grid-template-columns: 1fr 1fr; gap: clamp(1.2rem, 3vw, 2rem);
  align-items: start; margin: 1.5rem 0 2rem; max-width: var(--wide);
}
.spread .prose { max-width: none; }

.colophon {
  margin-top: 2rem; padding: 2.5rem var(--gutter) 4rem;
  border-top: 1px solid var(--rule); text-align: center;
}
.colophon p {
  font-family: var(--font-sans); font-size: 0.82rem; color: var(--ivory-mute);
  max-width: 28rem; margin: 0 auto 0.6rem; line-height: 1.5;
}
.colophon a { color: var(--copper); }

.reveal {
  opacity: 0; transform: translateY(12px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}
.reveal.in { opacity: 1; transform: none; }

.mobile-toc {
  display: none; position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--ink) 94%, transparent);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--rule-soft);
  padding: 0; font-family: var(--font-sans); font-size: 0.72rem;
  color: var(--copper); letter-spacing: 0.1em; text-transform: uppercase;
}
.mobile-toc-btn {
  display: flex; align-items: center; gap: 0.65rem;
  width: 100%; border: 0; background: transparent; color: inherit;
  font: inherit; letter-spacing: inherit; text-transform: inherit;
  padding: 0.75rem var(--gutter); cursor: pointer; text-align: left;
  -webkit-tap-highlight-color: transparent;
}
.mobile-toc-btn:hover,
.mobile-toc-btn:focus-visible {
  color: var(--ivory);
  outline: none;
  background: color-mix(in srgb, var(--paper) 55%, transparent);
}
.mobile-toc-icon {
  display: flex; flex-direction: column; justify-content: center; gap: 4px;
  width: 1.15rem; flex: 0 0 auto;
}
.mobile-toc-icon span {
  display: block; height: 1.5px; width: 100%;
  background: currentColor; border-radius: 1px;
  transition: transform 0.18s ease, opacity 0.18s ease;
}
body.toc-open .mobile-toc-icon span:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}
body.toc-open .mobile-toc-icon span:nth-child(2) { opacity: 0; }
body.toc-open .mobile-toc-icon span:nth-child(3) {
  transform: translateY(-5.5px) rotate(-45deg);
}
.mobile-toc-label { flex: 1 1 auto; min-width: 0; }
.mobile-toc-hint {
  flex: 0 0 auto;
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  color: var(--ivory-mute);
  text-transform: uppercase;
}
.toc-backdrop {
  display: none;
  position: fixed; inset: 0;
  background: rgba(0, 0, 0, 0.55);
  z-index: 110;
  border: 0; padding: 0; margin: 0; cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.toc-close {
  display: none;
  align-self: flex-end;
  margin: 0 0 0.5rem auto;
  border: 1px solid var(--rule-soft);
  background: var(--paper);
  color: var(--ivory-dim);
  font-family: var(--font-sans);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.4rem 0.7rem;
  border-radius: 4px;
  cursor: pointer;
}
.toc-close:hover { color: var(--ivory); border-color: var(--copper-dim); }

/* Floating GitHub source button */
.github-fab {
  position: fixed;
  right: max(1rem, env(safe-area-inset-right, 0px));
  bottom: max(1rem, env(safe-area-inset-bottom, 0px));
  z-index: 90;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.7rem 0.95rem 0.7rem 0.8rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--paper-lift) 92%, #000);
  border: 1px solid var(--rule);
  color: var(--ivory);
  text-decoration: none;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(10px);
  -webkit-tap-highlight-color: transparent;
  transition: transform 0.15s ease, border-color 0.15s ease, color 0.15s ease,
    background 0.15s ease, box-shadow 0.15s ease;
}
.github-fab:hover,
.github-fab:focus-visible {
  color: #fff;
  border-color: var(--copper);
  background: color-mix(in srgb, var(--paper) 70%, #000);
  box-shadow: 0 10px 32px rgba(0, 0, 0, 0.5);
  transform: translateY(-2px);
  outline: none;
}
.github-fab:active { transform: translateY(0); }
.github-fab-icon {
  display: block;
  flex: 0 0 auto;
}
.github-fab-label {
  line-height: 1;
  padding-right: 0.1rem;
}
@media (max-width: 520px) {
  /* Icon-first on small phones; label stays for discoverability */
  .github-fab {
    padding: 0.75rem 0.85rem;
    gap: 0.4rem;
  }
  .github-fab-label {
    font-size: 0.72rem;
  }
}
/* Sit above the mobile menu bar zone without covering chapter content too hard */
@media (max-width: 920px) {
  .github-fab {
    bottom: max(1rem, env(safe-area-inset-bottom, 0px));
    z-index: 95;
  }
}

/* ── Monograph density: contracts, algorithms, defs ── */
.contract {
  max-width: var(--wide);
  margin: 1.4rem 0 1.8rem;
  border: 1px solid var(--ray);
  border-radius: 2px;
  background: color-mix(in srgb, var(--paper) 80%, #0a1520);
  overflow: hidden;
}
.contract-bar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 0.5rem 1rem;
  background: color-mix(in srgb, var(--ray) 12%, var(--paper));
  border-bottom: 1px solid color-mix(in srgb, var(--ray) 30%, var(--rule));
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--ray-hot);
}
.contract-body { padding: 1rem 1.15rem 1.15rem; }
.contract-body p { margin: 0 0 0.65rem; color: var(--ivory-dim); font-size: 0.94rem; }
.contract-body p:last-child { margin-bottom: 0; }
.contract-body ul { margin: 0.4rem 0 0; padding-left: 1.15rem; color: var(--ivory-dim); font-size: 0.92rem; }
.contract-body li { margin-bottom: 0.3rem; }

.algo {
  max-width: var(--wide);
  margin: 1.3rem 0 1.7rem;
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: #0d1016;
  counter-reset: algo-line;
}
.algo-bar {
  padding: 0.45rem 1rem;
  border-bottom: 1px solid var(--rule-soft);
  font-family: var(--font-sans); font-size: 0.66rem; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--copper);
  background: var(--paper);
}
.algo ol {
  margin: 0; padding: 0.85rem 1rem 1rem 2.4rem;
  font-family: var(--font-mono); font-size: 0.78rem;
  line-height: 1.65; color: var(--ivory-dim);
}
.algo li { margin-bottom: 0.35rem; padding-left: 0.25rem; }
.algo li::marker { color: var(--copper-dim); }
.algo .em { color: var(--ray-hot); }
.algo .cm { color: #6a7368; }

.defgrid {
  display: grid;
  grid-template-columns: minmax(7rem, 0.35fr) 1fr;
  gap: 0;
  max-width: var(--wide);
  margin: 1.2rem 0 1.6rem;
  border: 1px solid var(--rule);
  border-radius: 2px;
  overflow: hidden;
  font-family: var(--font-sans); font-size: 0.86rem;
}
.defgrid dt, .defgrid dd {
  margin: 0; padding: 0.65rem 0.85rem;
  border-bottom: 1px solid var(--rule-soft);
}
.defgrid dt {
  background: var(--paper);
  color: var(--copper);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  border-right: 1px solid var(--rule-soft);
}
.defgrid dd { color: var(--ivory-dim); }
.defgrid dt:last-of-type, .defgrid dd:last-of-type { border-bottom: 0; }

.stage-stack {
  max-width: var(--wide);
  margin: 1.4rem 0 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}
.stage {
  border: 1px solid var(--rule);
  border-left: 3px solid var(--copper);
  background: var(--paper);
  border-radius: 0 2px 2px 0;
  padding: 0.9rem 1.1rem;
}
.stage.ray { border-left-color: var(--ray); }
.stage .stage-id {
  font-family: var(--font-sans); font-size: 0.64rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 0.25rem;
}
.stage.ray .stage-id { color: var(--ray); }
.stage h4 {
  font-family: var(--font-display); font-size: 1.1rem; font-weight: 500;
  margin: 0 0 0.4rem; color: var(--ivory); text-transform: none; letter-spacing: 0;
}
.stage p { margin: 0; color: var(--ivory-dim); font-size: 0.92rem; line-height: 1.5; }
.stage code { font-size: 0.84em; }

.thesis-box {
  max-width: var(--measure);
  margin: 0 0 2rem;
  padding: 1.25rem 1.4rem;
  border: 1px solid var(--copper-dim);
  background: linear-gradient(135deg, color-mix(in srgb, var(--copper) 8%, var(--paper)), var(--ink-soft));
  border-radius: 2px;
}
.thesis-box .label {
  font-family: var(--font-sans); font-size: 0.64rem; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--copper); margin-bottom: 0.5rem;
}
.thesis-box p {
  margin: 0; font-family: var(--font-display); font-size: 1.15rem;
  line-height: 1.45; color: var(--ivory); font-weight: 400;
}

.wide-prose { max-width: var(--wide); }
.wide-prose p { color: var(--ivory-dim); }
.data-table.compact td, .data-table.compact th { padding: 0.45rem 0.55rem; font-size: 0.8rem; }
.data-table .mono { font-family: var(--font-mono); font-size: 0.78em; color: var(--ray-hot); }

.section-rule {
  display: flex; align-items: center; gap: 1rem;
  max-width: var(--wide); margin: 2.8rem 0 1.2rem;
}
.section-rule::after {
  content: ""; flex: 1; height: 1px; background: var(--rule);
}
.section-rule h2 {
  font-family: var(--font-display); font-weight: 500; font-size: 1.45rem;
  margin: 0; color: var(--ivory); white-space: nowrap;
}

@media (max-width: 920px) {
  .book { margin-left: 0; }
  .mobile-toc { display: block; }

  /* Off-canvas chapter drawer (same TOC as desktop) */
  .toc {
    display: flex;
    position: fixed;
    top: 0; left: 0;
    width: min(88vw, 300px);
    height: 100%;
    height: 100dvh;
    max-height: 100dvh;
    transform: translateX(-105%);
    transition: transform 0.22s ease;
    z-index: 120;
    box-shadow: 8px 0 32px rgba(0, 0, 0, 0.45);
    padding-top: 0.9rem;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
  }
  .toc.is-open { transform: translateX(0); }
  .toc-close { display: inline-flex; }
  .toc-backdrop {
    display: block;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
  }
  body.toc-open .toc-backdrop {
    opacity: 1;
    pointer-events: auto;
  }
  body.toc-open { overflow: hidden; touch-action: none; }

  .compare, .spread { grid-template-columns: 1fr; }
  .file-map .row { grid-template-columns: 1fr; gap: 0.2rem; }
  .pager { grid-template-columns: 1fr; }
  .pager .next { text-align: left; }
}

/* Safe area for notched phones */
@supports (padding: max(0px)) {
  @media (max-width: 920px) {
    .mobile-toc-btn {
      padding-left: max(var(--gutter), env(safe-area-inset-left));
      padding-right: max(var(--gutter), env(safe-area-inset-right));
    }
    .toc {
      padding-left: max(0.9rem, env(safe-area-inset-left));
      padding-bottom: max(2rem, env(safe-area-inset-bottom));
    }
  }
}

/* ── Pedagogy: jargon, why, dual-pane, full-page plate ── */
.jargon {
  max-width: var(--measure);
  margin: 0.9rem 0 1.2rem;
  padding: 0.75rem 1rem;
  border-left: 3px solid var(--ray);
  background: color-mix(in srgb, var(--ray) 8%, var(--paper));
  border-radius: 0 2px 2px 0;
}
.jargon .j-term {
  font-family: var(--font-sans);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ray-hot);
  margin-bottom: 0.25rem;
}
.jargon p { margin: 0; color: var(--ivory-dim); font-size: 0.92rem; line-height: 1.5; }
.jargon p + p { margin-top: 0.4rem; }

.why-callout {
  max-width: var(--measure);
  margin: 0.85rem 0 1.15rem;
  padding: 0.85rem 1.05rem;
  border: 1px solid color-mix(in srgb, var(--emerald) 35%, var(--rule));
  background: color-mix(in srgb, var(--emerald) 7%, var(--ink-soft));
  border-radius: 2px;
}
.why-callout .why-label {
  font-family: var(--font-sans);
  font-size: 0.66rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--emerald);
  margin-bottom: 0.3rem;
}
.why-callout p { margin: 0; color: var(--ivory-dim); font-size: 0.93rem; line-height: 1.5; }

.dual-pane {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 1rem;
  max-width: var(--wide);
  margin: 1.2rem 0 1.6rem;
  align-items: stretch;
}
.dual-pane .pane {
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: #0d1016;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.dual-pane .pane-bar {
  padding: 0.4rem 0.85rem;
  background: var(--paper);
  border-bottom: 1px solid var(--rule-soft);
  font-family: var(--font-sans);
  font-size: 0.64rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ivory-mute);
}
.dual-pane .pane pre {
  margin: 0;
  padding: 0.85rem 1rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  line-height: 1.5;
  color: var(--ivory-dim);
  flex: 1;
}
.dual-pane .pane .math-block {
  margin: 0;
  border: 0;
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  max-width: none;
}
.dual-pane .ln { color: #5a6570; user-select: none; margin-right: 0.65rem; }
.dual-pane .kw { color: var(--ray); }
.dual-pane .cm { color: #6a7368; }
.dual-pane .num { color: var(--copper); }
@media (max-width: 860px) {
  .dual-pane { grid-template-columns: 1fr; }
}

.plate.fullpage {
  max-width: min(1100px, 96vw);
  margin-left: auto;
  margin-right: auto;
}
.plate.fullpage .plate-frame {
  background: #0a0b0e;
}
.plate.fullpage .plate-frame img,
.plate.fullpage .plate-frame object,
.plate.fullpage .plate-frame svg {
  width: 100%;
  height: auto;
  display: block;
}
.concept-badge {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--warn);
  border: 1px solid color-mix(in srgb, var(--warn) 45%, transparent);
  padding: 0.15rem 0.45rem;
  border-radius: 3px;
  margin-right: 0.4rem;
  vertical-align: middle;
}
.real-badge {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--emerald);
  border: 1px solid color-mix(in srgb, var(--emerald) 45%, transparent);
  padding: 0.15rem 0.45rem;
  border-radius: 3px;
  margin-right: 0.4rem;
}
.plate-cap .concept-badge + strong,
.plate-cap .real-badge + strong { display: inline; }
.strip-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  max-width: var(--wide);
  margin: 1rem 0;
}
.strip-row img { width: 100%; height: auto; display: block; border: 1px solid var(--rule); border-radius: 2px; }
@media (max-width: 700px) { .strip-row { grid-template-columns: 1fr; } }

.nee-step {
  max-width: var(--wide);
  margin: 1.4rem 0 1.8rem;
  border: 1px solid var(--rule);
  border-radius: 2px;
  overflow: hidden;
  background: var(--ink-soft);
}
.nee-step-head {
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
  padding: 0.7rem 1rem;
  background: var(--paper);
  border-bottom: 1px solid var(--rule-soft);
}
.nee-step-head .sn {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--copper);
}
.nee-step-head h4 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--ivory);
  text-transform: none;
  letter-spacing: 0;
}
.nee-step-body { padding: 1rem 1.1rem 1.15rem; }
.nee-step-body > p { margin: 0 0 0.75rem; color: var(--ivory-dim); font-size: 0.95rem; }

/* ── Glossary hover terms ── */
.term {
  position: relative;
  display: inline;
  cursor: help;
  color: inherit;
  border-bottom: 1px dotted color-mix(in srgb, var(--ray) 70%, transparent);
  text-decoration: none;
}
.term:hover,
.term:focus {
  color: var(--ray-hot);
  outline: none;
  border-bottom-color: var(--ray-hot);
}
.term-tip {
  position: absolute;
  left: 50%;
  bottom: calc(100% + 10px);
  transform: translateX(-50%);
  width: min(280px, 70vw);
  padding: 0.7rem 0.85rem 0.8rem;
  background: #12161f;
  border: 1px solid var(--ray);
  border-radius: 4px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.55);
  z-index: 80;
  pointer-events: none;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.12s ease, visibility 0.12s ease;
  text-align: left;
  white-space: normal;
  line-height: 1.45;
  font-weight: 400;
}
.term:hover .term-tip,
.term:focus .term-tip {
  opacity: 1;
  visibility: visible;
}
.term-tip::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 100%;
  transform: translateX(-50%);
  border: 7px solid transparent;
  border-top-color: var(--ray);
}
.term-tip.tip-left {
  left: auto;
  right: 0;
  transform: none;
}
.term-tip.tip-left::after {
  left: auto;
  right: 1.2rem;
  transform: none;
}
.term-tip.tip-up {
  bottom: auto;
  top: calc(100% + 10px);
}
.term-tip.tip-up::after {
  top: auto;
  bottom: 100%;
  border-top-color: transparent;
  border-bottom-color: var(--ray);
}
.term-tip-key {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ray-hot);
  margin-bottom: 0.2rem;
  letter-spacing: 0.02em;
}
.term-tip-expand {
  display: block;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  color: var(--copper);
  margin-bottom: 0.4rem;
  letter-spacing: 0.02em;
}
.term-tip-def {
  display: block;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--ivory-dim);
}

/* Glossary page cards */
.gloss-grid {
  display: grid;
  gap: 0.75rem;
  max-width: var(--wide);
  margin: 1rem 0 2rem;
}
.gloss-card {
  border: 1px solid var(--rule);
  border-radius: 2px;
  background: var(--paper);
  padding: 0.9rem 1.1rem;
}
.gloss-card h3 {
  margin: 0 0 0.25rem;
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--ray-hot);
}
.gloss-card .expand {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: var(--copper);
  margin-bottom: 0.45rem;
}
.gloss-card p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--ivory-dim);
  line-height: 1.5;
}
.gloss-group {
  font-family: var(--font-sans);
  font-size: 0.68rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--copper);
  margin: 2rem 0 0.75rem;
  max-width: var(--wide);
}
.gloss-search {
  max-width: var(--measure);
  margin: 0 0 1.5rem;
}
.gloss-search input {
  width: 100%;
  padding: 0.65rem 0.9rem;
  background: var(--ink-soft);
  border: 1px solid var(--rule);
  border-radius: 2px;
  color: var(--ivory);
  font-family: var(--font-sans);
  font-size: 0.95rem;
}
.gloss-search input:focus {
  outline: none;
  border-color: var(--ray);
}
.gloss-hint {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--ivory-mute);
  max-width: var(--measure);
  margin: 0 0 1.25rem;
}

/* KaTeX inside math-block plates */
.math-block .katex-display {
  margin: 0.4rem 0;
  overflow-x: auto;
  overflow-y: hidden;
}
.math-block .katex {
  font-size: 1.12em;
  color: var(--ivory);
}
.math-block {
  text-align: center;
}

/* Nested tree TOC — collapsible branches (collapsed by default) */
.toc-legacy { display: none !important; } /* replaced by #toc-mount nav */

.toc-branch {
  border: 0;
  margin: 0.1rem 0;
}
.toc-branch > .toc-summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-family: var(--font-sans);
  font-size: 0.74rem;
  color: var(--ivory-mute);
  padding: 0.38rem 0.45rem;
  border-radius: 4px;
  border-left: 2px solid transparent;
  user-select: none;
  line-height: 1.3;
}
.toc-branch > .toc-summary::-webkit-details-marker { display: none; }
.toc-branch > .toc-summary::marker { content: ""; }
.toc-branch > .toc-summary:hover {
  color: var(--ivory);
  background: var(--paper);
}
.toc-branch.is-current > .toc-summary {
  color: var(--ivory);
  border-left-color: var(--copper-dim);
}
.toc-chevron {
  flex: 0 0 auto;
  width: 0.45rem;
  height: 0.45rem;
  border-right: 1.5px solid var(--copper-dim);
  border-bottom: 1.5px solid var(--copper-dim);
  transform: rotate(-45deg);
  transition: transform 0.15s ease;
  margin: 0 0.15rem 0 0.1rem;
  opacity: 0.85;
}
.toc-branch[open] > .toc-summary .toc-chevron {
  transform: rotate(45deg);
  margin-top: -0.1rem;
}
.toc-summary-text {
  flex: 1 1 auto;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.toc-count {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--copper-dim);
  opacity: 0.9;
  padding: 0.05rem 0.3rem;
  border: 1px solid var(--rule-soft);
  border-radius: 999px;
  line-height: 1.2;
}
.toc-children {
  display: flex;
  flex-direction: column;
  gap: 0.02rem;
  padding: 0.1rem 0 0.35rem 0.15rem;
  border-left: 1px solid var(--rule-soft);
  margin: 0 0 0.15rem 0.65rem;
}
.toc a.toc-leaf {
  padding-left: 0.65rem;
  font-size: 0.72rem;
}
.toc a.toc-hub {
  font-weight: 500;
  color: var(--ivory-dim);
  padding-left: 0.65rem;
  font-size: 0.74rem;
}

.tree-card {
  display: block; text-decoration: none; padding: 1rem 1.1rem;
  background: var(--paper); border: 1px solid var(--rule); border-radius: 2px;
  transition: border-color 0.15s;
}
.tree-card:hover { border-color: var(--ray); }
.tree-card .num {
  font-family: var(--font-mono); font-size: 0.68rem; color: var(--copper); margin-bottom: 0.3rem;
}
.tree-card h3 {
  font-family: var(--font-display); font-size: 1.1rem; margin: 0 0 0.35rem; color: var(--ivory); font-weight: 500;
}
.tree-card p { margin: 0; font-family: var(--font-sans); font-size: 0.82rem; color: var(--ivory-mute); line-height: 1.45; }

/* Unit diagrams */
.diagram-plate { padding: 0.5rem; overflow-x: auto; }
.diagram-plate svg.unit-diagram { width: 100%; max-width: 44rem; height: auto; display: block; margin: 0 auto; }
.code-block {
  background: var(--paper); border: 1px solid var(--rule); border-radius: 4px;
  padding: 1rem 1.1rem; overflow-x: auto; font-family: var(--font-mono);
  font-size: 0.78rem; line-height: 1.45; color: var(--ivory-dim);
  white-space: pre; margin: 0.75rem 0 1.25rem;
}
.code-block code { font-family: inherit; color: inherit; background: none; padding: 0; }

/* Narrative monograph — citations, key ideas, figures (Wave 0) */
.citation-chip {
  display: flex; flex-direction: column; gap: 0.3rem;
  border-left: 2px solid var(--ray-hot);
  background: var(--paper); border-radius: 0 4px 4px 0;
  padding: 0.6rem 0.85rem; margin: 0.6rem 0 1rem;
}
.citation-chip .citation-code {
  font-family: var(--font-mono); font-size: 0.76rem; line-height: 1.4;
  color: var(--ivory-dim); white-space: pre-wrap; word-break: break-word;
}
.citation-chip .citation-loc {
  font-family: var(--font-mono); font-size: 0.72rem; color: var(--ray-hot);
  text-decoration: none; letter-spacing: 0.02em;
}
.citation-chip .citation-loc:hover { text-decoration: underline; }
.key-idea {
  border-left: 3px solid var(--emerald); background: var(--paper-lift);
  padding: 0.85rem 1.1rem; margin: 1rem 0; border-radius: 0 4px 4px 0;
}
.key-idea .key-label {
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--emerald); margin-bottom: 0.35rem;
}
.key-idea p { margin: 0; color: var(--ivory-dim); font-size: 0.95rem; line-height: 1.55; }
figure.unit-figure { margin: 1.25rem 0; padding: 0; }
figure.unit-figure img { width: 100%; max-width: 44rem; height: auto; display: block; margin: 0 auto; }
figure.unit-figure figcaption {
  font-family: var(--font-mono); font-size: 0.72rem; color: var(--ivory-mute);
  text-align: center; margin-top: 0.5rem; letter-spacing: 0.02em;
}