:root {
  --bg: #f5f5f7;
  --surface: #ffffff;
  --panel: #eef1f5;
  --text: #1c1c1e;
  --muted: #4a4a4c;
  --border: #e4e6eb;
  --accent: #4fa3a4;
  --accent-contrast: #ffffff;
  --shadow: 0 18px 36px rgba(0, 0, 0, 0.14);
  --ui: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter", system-ui, sans-serif;
  --body: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter", system-ui, sans-serif;
}

:root[data-theme="dark"] {
  --bg: #0f1115;
  --surface: #151821;
  --panel: #12151d;
  --text: #e8ecf1;
  --muted: #a0a6b4;
  --border: #1f2430;
  --accent: #8cd6c3;
  --accent-contrast: #0f1115;
  --shadow: 0 22px 48px rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 18px;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
}

:root[data-theme="dark"] body { background: var(--bg); }

::selection {
  background: color-mix(in oklab, var(--accent) 35%, transparent);
  color: var(--accent-contrast);
}

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover {
  color: color-mix(in oklab, var(--accent) 85%, var(--text));
  text-decoration: underline;
  text-decoration-thickness: 0.09em;
  text-underline-offset: 4px;
}

.hero {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 5%;
  background: var(--surface);
  position: relative;
  color: var(--text);
  overflow: hidden;
}
.flow-lines {
  z-index: 0;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  opacity: 0.12;
}
.flow-lines path {
  stroke-dasharray: 2000;
  stroke-dashoffset: 2000;
  animation-name: lineDance;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
}
@keyframes lineDance {
  0% { stroke-dashoffset: 1800; }
  50% { stroke-dashoffset: 0; }
  100% { stroke-dashoffset: -1800; }
}
.hero-content {
  position: relative;
  z-index: 1;
  max-width: 640px;
  padding-right: 60px;
}
.hero-title {
  font-size: clamp(2.6rem, 4vw, 3.6rem);
  font-weight: 700;
  margin: 0 0 18px;
  line-height: 1.2;
}
.hero-subtitle {
  font-size: 1.1rem;
  opacity: 0.9;
  line-height: 1.6;
  margin-bottom: 26px;
}
.hero-buttons {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.primary-btn, .secondary-btn {
  padding: 12px 20px;
  font-size: 1rem;
  border-radius: 14px;
  border: none;
  cursor: pointer;
  transition: 0.2s;
  font-weight: 600;
  font-family: var(--ui);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
}
.primary-btn {
  background: var(--text);
  color: var(--surface);
  box-shadow: 0 10px 24px rgba(0,0,0,0.14);
}
.primary-btn:hover { opacity: 0.9; transform: translateY(-1px); }
.secondary-btn {
  background: rgba(255,255,255,0.15);
  color: var(--surface);
  border: 1px solid rgba(255,255,255,0.35);
  backdrop-filter: blur(8px);
}
.secondary-btn:hover { opacity: 0.8; }
.download-btn {
  display: none !important;
}
.hero-cover {
  position: relative;
  z-index: 1;
}
.hero-cover img {
  width: 340px;
  max-width: 90vw;
  height: auto;
  border-radius: 20px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.25);
  object-fit: cover;
}

/* Mobile hero layout */
@media (max-width: 820px) {
  .hero {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 56px 1.4rem 88px;
    gap: 1.6rem;
  }
  .hero-content {
    padding-right: 0;
    max-width: 100%;
  }
  .hero-buttons { justify-content: center; }
  .hero-cover img {
    width: 78vw;
    max-width: 420px;
  }
}

/* Mobile glass nav */
.mobile-nav {
  position: fixed;
  top: calc(env(safe-area-inset-top) + 8px);
  left: 50%;
  transform: translateX(-50%);
  z-index: 60;
  display: none;
  align-items: center;
  gap: .4rem;
  padding: .45rem .55rem;
  border-radius: 999px;
  background: color-mix(in oklab, var(--surface) 70%, transparent);
  border: 1px solid color-mix(in oklab, var(--border) 65%, transparent);
  backdrop-filter: blur(14px) saturate(110%);
  -webkit-backdrop-filter: blur(14px) saturate(110%);
  box-shadow: 0 12px 26px rgba(0,0,0,0.12);
  transition: transform .2s ease, opacity .2s ease;
}
.mobile-nav.hidden {
  opacity: 1;
  transform: translate(-50%, -80%);
}
.mobile-nav button {
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  background: color-mix(in oklab, var(--panel) 65%, var(--surface));
  color: var(--text);
  border-radius: 12px;
  padding: .45rem .9rem;
  font-weight: 600;
  font-family: var(--ui);
  min-width: 90px;
  flex: 1 1 0;
  cursor: pointer;
  box-shadow: 0 6px 14px rgba(0,0,0,0.08);
}
.mobile-nav button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  box-shadow: none;
}
.mobile-nav .toc-btn {
  min-width: 90px;
}
@media (max-width: 960px) {
  .mobile-nav { display: flex; }
  body.mobile-nav-active { padding-top: 68px; }
}

.section {
  width: min(1100px, 90vw);
  margin: 0 auto;
  padding: 60px 0;
}
.section h2 {
  font-size: 2rem;
  margin-bottom: 20px;
  font-family: var(--ui);
}
.section p {
  font-size: 1.05rem;
  line-height: 1.7;
  opacity: 0.9;
}

.masthead {
  position: sticky;
  top: 0;
  z-index: 30;
  background: color-mix(in oklab, var(--surface) 98%, transparent);
  border-bottom: 1px solid color-mix(in oklab, var(--border) 80%, transparent);
  box-shadow: 0 12px 28px rgba(0,0,0,.08);
  backdrop-filter: blur(10px) saturate(120%);
  -webkit-backdrop-filter: blur(10px) saturate(120%);
}
.masthead-inner {
  width: min(1200px, 94vw);
  margin: 0 auto;
  padding: 1rem clamp(1rem, 3vw, 1.6rem);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.masthead-left {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-width: 0;
}
.eyebrow {
  text-transform: uppercase;
  letter-spacing: .18em;
  font-size: .78rem;
  color: var(--muted);
  margin: 0 0 .25rem;
}
.masthead-title {
  font-family: var(--ui);
  font-size: clamp(1.6rem, 3vw, 2.25rem);
  margin: 0;
  letter-spacing: -0.01em;
}
.masthead-subtitle {
  margin: .1rem 0 0;
  color: var(--muted);
  font-size: 1rem;
}
.masthead-actions {
  display: flex;
  align-items: center;
  gap: .5rem;
}
.pill-btn {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .65rem 1rem;
  border-radius: 999px;
  border: 1px solid color-mix(in oklab, var(--accent) 40%, var(--border));
  background: color-mix(in oklab, var(--accent) 12%, var(--surface));
  color: var(--text);
  font-weight: 700;
  font-family: var(--ui);
  text-decoration: none;
  box-shadow: 0 12px 22px rgba(0,0,0,.08);
  transition: transform .12s ease, box-shadow .18s ease, background .18s ease, border-color .18s ease;
}
.pill-btn.secondary {
  background: color-mix(in oklab, var(--surface) 95%, transparent);
  border-color: color-mix(in oklab, var(--border) 75%, transparent);
}
.pill-btn:hover { transform: translateY(-1px); box-shadow: 0 16px 28px rgba(0,0,0,.12); }
.pill-btn:active { transform: translateY(0); }

.reading-area {
  padding: 0 clamp(1rem, 3vw, 1.6rem) 3rem;
  background: var(--bg);
}

.layout {
  display: grid;
  grid-template-columns: minmax(260px, 320px) minmax(0, 1fr);
  gap: 1.25rem;
  width: min(1200px, 94vw);
  margin: 1.5rem auto 0;
  align-items: start;
  transition: grid-template-columns .2s ease;
}

.sidebar {
  position: sticky;
  top: 2rem;
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  background: color-mix(in oklab, var(--surface) 96%, transparent);
  border-radius: 12px;
  box-shadow: 0 10px 24px rgba(0,0,0,0.08);
  display: flex;
  flex-direction: column;
  padding: 0.5rem 0.75rem 0.75rem 0.25rem;
  max-height: calc(100vh - 4rem);
  overflow: hidden;
  min-height: 0;
  gap: 0.6rem;
}

/* Collapsed sidebar on desktop */
:root.sidebar-collapsed .layout { grid-template-columns: 0 1fr; }
:root.sidebar-collapsed .sidebar {
  width: 0 !important;
  padding: 0 !important;
  overflow: hidden !important;
  border: none !important;
  box-shadow: none !important;
}
.icon-button {
  all: unset;
  display: grid;
  place-items: center;
  width: 36px; height: 36px;
  border-radius: 10px;
  cursor: pointer;
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  background: color-mix(in oklab, var(--surface) 80%, transparent);
  color: var(--text);
  transition: transform .15s ease, background .2s ease, box-shadow .2s ease;
}
.icon-button:hover {
  background: color-mix(in oklab, var(--accent) 14%, transparent);
  box-shadow: 0 10px 24px rgba(0,0,0,.12);
  transform: translateY(-1px);
}

.toc {
  display: flex;
  flex-direction: column;
  gap: .25rem;
  padding: 0.5rem 0 .25rem;
  overflow: auto;
  flex: 1;
  margin-top: .25rem;
  min-height: 0;
}
.toc a {
  display: block;
  padding: .45rem .55rem;
  border-radius: 8px;
  color: var(--text);
  font-family: var(--ui);
  font-weight: 600;
  letter-spacing: .005em;
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: background .16s ease, color .14s ease, border-color .18s ease;
}
.toc a:hover {
  background: color-mix(in oklab, var(--accent) 6%, transparent);
  border-color: color-mix(in oklab, var(--accent) 40%, transparent);
}
.toc a.active {
  background: color-mix(in oklab, var(--accent) 10%, var(--surface));
  color: var(--text);
  border-color: var(--accent);
}
.toc .section { margin: .4rem 0; }
.toc .section-title {
  margin: .65rem .25rem .35rem;
  font-size: .78rem;
  color: var(--muted);
  font-weight: 600;
  font-family: var(--ui);
  text-transform: uppercase;
  letter-spacing: .12em;
}
.content {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}
.page .chapter {
  scroll-margin-top: 96px;
}
.page .chapter + .chapter {
  margin-top: 2.6rem;
  padding-top: 2rem;
  border-top: 1px solid color-mix(in oklab, var(--border) 72%, transparent);
}
.page {
  position: relative;
  max-width: 88ch;
  padding: 2.1rem clamp(1rem, 3vw, 2.4rem);
  margin: 0 auto;
  width: 100%;
  background: var(--surface);
  border: 1px solid color-mix(in oklab, var(--border) 72%, transparent);
  border-radius: 18px;
  box-shadow: var(--shadow);
  /* Defensive: allow breaking long tokens to avoid viewport overflow */
  overflow-wrap: anywhere;
  user-select: none;
  -webkit-user-select: none;
}
.page h1, .page h2, .page h3, .page h4 {
  line-height: 1.2;
  font-family: var(--ui);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
  text-rendering: optimizeLegibility;
}
.page h1 { font-size: clamp(2.2rem, 4vw, 2.9rem); margin: 0 0 .9rem; }
.page h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); margin: 2.1rem 0 .65rem; }
.page h3 { font-size: clamp(1.3rem, 2.6vw, 1.65rem); margin: 1.6rem 0 .55rem; }
.page h4 { font-size: clamp(1.1rem, 2.2vw, 1.3rem); margin: 1.2rem 0 .45rem; font-weight: 600; }
.page p { margin: .85rem 0; color: var(--text); }
.page p, .page li, .page blockquote, .page dd, .page h1, .page h2, .page h3, .page h4, .page table caption, .page .tablenotes {
  overflow-wrap: break-word; word-break: normal; hyphens: auto; -webkit-hyphens: auto;
}
.page strong { font-weight: 700; color: color-mix(in oklab, var(--text) 95%, var(--accent)); }
.page em { color: color-mix(in oklab, var(--text) 86%, var(--accent)); }
.page a {
  color: color-mix(in oklab, var(--accent) 90%, var(--text));
  text-decoration: underline;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 4px;
}
.page img, .page video, .page iframe { max-width: 100%; height: auto; border-radius: 10px; }
.page .table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding: .35rem;
  border-radius: 14px;
  margin: 1.1rem 0;
  background: color-mix(in oklab, var(--surface) 92%, var(--bg));
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  box-shadow: inset 0 1px 0 color-mix(in oklab, var(--border) 40%, transparent);
  display: flex;
  justify-content: center;
}
.page pre {
  background: color-mix(in oklab, var(--surface) 88%, var(--bg));
  padding: 1rem;
  border-radius: 12px;
  overflow: auto;
  font-family: "IBM Plex Mono", "SFMono-Regular", Menlo, monospace;
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  box-shadow: inset 0 1px 0 color-mix(in oklab, var(--border) 35%, transparent);
}
.page code {
  font-family: "IBM Plex Mono", "SFMono-Regular", Menlo, monospace;
  font-size: .95em;
  background: color-mix(in oklab, var(--surface) 85%, var(--bg));
  padding: 0 .35em;
  border-radius: .35em;
}
.page blockquote {
  border-left: 4px solid color-mix(in oklab, var(--accent) 45%, var(--border));
  margin: 1.25rem 0;
  padding: .6rem 1.2rem;
  color: color-mix(in oklab, var(--text) 85%, var(--muted));
  background: color-mix(in oklab, var(--surface) 88%, var(--bg));
  border-radius: 12px;
  box-shadow: inset 0 1px 0 color-mix(in oklab, var(--border) 40%, transparent);
}
.page dl { margin: 1rem 0; }
.page dt { font-weight: 600; margin-top: .5rem; }
.page dd { margin: .25rem 0 .5rem 1rem; }
.page .math, .katex-display { overflow-x: auto; }
.page mjx-container { max-width: 100%; overflow-x: auto; }
.page mjx-container[display="true"] { display: block; max-width: 100%; overflow-x: auto; }
.page mjx-container, .page math { font-family: var(--body) !important; font-size: 0.95em !important; }
/* Center display-style math from MathJax, KaTeX, and native MathML */
.page mjx-container[display="true"],
.page .MathJax_Display,
.page .katex-display,
.page math[display="block"],
.page p > math:only-child,
.page .math.display {
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}
/* Slightly smaller display math to tuck formulas into flow */
.page mjx-container[display="true"], .page math[display="block"] { font-size: 0.82em !important; }
/* Ensure MathJax internals inherit the scaled size */
.page mjx-container * { font-size: inherit !important; }
/* Center equation images that appear alone in a paragraph */
.page p:has(> img:only-child) { text-align: center; }
.page p:has(> img:only-child) > img { display: inline-block; }
.page p.equation-line { text-align: center; }
.page .subtitle { margin-top: -.5rem; color: var(--muted); }
.page section.example {
  border: 1px solid color-mix(in oklab, var(--accent) 28%, var(--border));
  border-radius: 12px;
  padding: 1.1rem;
  margin: 1.1rem 0;
  background: color-mix(in oklab, var(--surface) 92%, var(--bg));
  box-shadow: inset 0 1px 0 color-mix(in oklab, var(--border) 40%, transparent);
}
.page section.example h3 { margin-top: 0; }
.page ul { padding-left: 1.25rem; }
/* Inline highlight chip used in Chapter 1 */
.page .hl { background: color-mix(in oklab, var(--accent) 15%, transparent); color: var(--text); padding: 0 .35em; border-radius: .35em; }
.page .label { color: var(--muted); margin-left: .35rem; white-space: nowrap; }

/* Example cards */
.page .example-card {
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  border-radius: 12px;
  padding: 1rem 1.1rem;
  margin: 1rem 0;
  background: color-mix(in oklab, var(--surface) 95%, var(--bg));
  box-shadow: 0 8px 18px rgba(0,0,0,0.08);
}
.page .example-card h3 { margin: 0 0 .35rem; }
.page .example-card .example-meta { padding-bottom: .5rem; border-bottom: 1px solid color-mix(in oklab, var(--border) 75%, transparent); }
.page .example-card .example-meta p { margin: .2rem 0; color: var(--muted); }
.page .example-card .example-body { padding-top: .6rem; display: grid; gap: .35rem; }
.page .example-breakdown ul {
  list-style: none;
  padding-left: 0;
  margin: .35rem 0 0;
  display: grid;
  gap: .35rem;
}
.page .example-breakdown li {
  padding: .4rem .6rem;
  border-left: 3px solid color-mix(in oklab, var(--accent) 55%, transparent);
  background: color-mix(in oklab, var(--surface) 92%, var(--bg));
  border-radius: 8px;
}
.page .pill {
  display: inline-block;
  padding: .12rem .55rem;
  border-radius: 999px;
  font-size: .9em;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--text);
}
.page .pill-purpose { background: color-mix(in oklab, #f29d38 28%, var(--surface)); border: 1px solid color-mix(in oklab, #f29d38 52%, transparent); }
.page .pill-method { background: color-mix(in oklab, #3580ff 26%, var(--surface)); border: 1px solid color-mix(in oklab, #3580ff 50%, transparent); }
.page .pill-findings { background: color-mix(in oklab, #9b6dfa 18%, var(--surface)); border: 1px solid color-mix(in oklab, #9b6dfa 45%, transparent); }
.page .pill-implications { background: color-mix(in oklab, #f0c27b 20%, var(--surface)); border: 1px solid color-mix(in oklab, #f0c27b 45%, transparent); }

.highlight-pulse {
  animation: pulse-bg 1s ease-in-out alternate infinite;
  background: color-mix(in oklab, var(--accent) 18%, var(--surface));
  border-radius: 10px;
}
@keyframes pulse-bg {
  from { box-shadow: 0 0 0 rgba(0,0,0,0); }
  to   { box-shadow: 0 0 0 6px color-mix(in oklab, var(--accent) 14%, transparent); }
}

.ask-chat {
  position: fixed;
  bottom: calc(env(safe-area-inset-bottom) + 1rem);
  left: 50%;
  transform: translateX(-50%);
  z-index: 50;
  display: flex;
  align-items: center;
}
.ask-pill {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .6rem .8rem;
  border-radius: 999px;
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  background: linear-gradient(135deg, color-mix(in oklab, var(--surface) 70%, transparent), color-mix(in oklab, var(--panel) 60%, transparent));
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 16px 32px rgba(0,0,0,0.14);
  cursor: text;
  min-width: 210px;
  width: 210px;
  transition: width .3s ease, box-shadow .28s ease, background .28s ease, transform .28s ease;
}
.ask-chat.open .ask-pill {
  width: 520px;
  cursor: default;
  transform: translateY(-1px);
}
.ask-label {
  color: var(--text);
  font-family: var(--ui);
  font-weight: 600;
  white-space: nowrap;
  padding-left: .25rem;
}
.ask-pill input {
  flex: 1;
  min-width: 0;
  border: none;
  outline: none;
  box-shadow: none;
  background: transparent;
  color: var(--text);
  font-size: 1rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s ease;
}
.ask-chat.open .ask-pill input {
  opacity: 1;
  pointer-events: auto;
}
.ask-pill input::placeholder { color: color-mix(in oklab, var(--muted) 80%, var(--text)); }
.ask-pill button {
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid color-mix(in oklab, var(--border) 70%, transparent);
  background: color-mix(in oklab, var(--text) 12%, var(--panel));
  color: color-mix(in oklab, var(--text) 90%, var(--surface));
  cursor: pointer;
  font-size: 1.1rem;
}


/* Window-style wrapper for full examples */
.page .example-window {
  border: 1px solid color-mix(in oklab, var(--border) 80%, transparent);
  border-radius: 14px;
  background: color-mix(in oklab, var(--surface) 88%, var(--bg));
  box-shadow: 0 10px 28px rgba(0,0,0,.08);
  margin: 1.1rem 0 1.4rem;
  overflow: hidden;
}
.page .example-window .window-header {
  background: linear-gradient(90deg, color-mix(in oklab, var(--accent) 18%, transparent), transparent 70%);
  border-bottom: 1px solid color-mix(in oklab, var(--border) 75%, transparent);
  padding: .85rem clamp(.9rem, 2vw, 1.1rem);
}
.page .example-window .window-header h2 {
  margin: 0;
}
.page .example-window .window-body {
  padding: 1.1rem clamp(.85rem, 2vw, 1.3rem);
}
/* Ensure text in Chapter 1 example boxes is left-aligned */
.page .example-window,
.page .example-window .window-header,
.page .example-window .window-body,
.page section.example {
  text-align: left;
}
/* Force left alignment for all content inside the example boxes */
.page .example-window .window-body p,
.page .example-window .window-body p *,
.page section.example p,
.page section.example p * {
  text-align: left !important;
}
/* Cover page styles */
.page:has(> .cover:only-child) {
  max-width: none; /* full-bleed cover */
  padding: 0;      /* remove default page padding */
  margin: 0;
  border: none;
  box-shadow: none;
  background: none;
}
.page:has(> .cover:only-child)::before { display: none; }
.page:has(> .cover:only-child) .cover { border-radius: 0; }
.page .cover {
  position: relative;
  border-radius: 16px;
  overflow: hidden;
  min-height: min(92vh, 900px);
  display: grid; /* use grid to easily center content */
  place-items: center;
  background: #131b2b; /* slightly lighter base behind the image */
}
.page .cover-media {
  position: absolute;
  inset: 0;
  /* Path relative to this CSS file (assets/css/) -> ../images */
  background-image: url('../images/greenwich.png');
  background-size: cover;
  background-position: center;
  /* Lighten the image a touch for readability */
  filter: saturate(1.08) contrast(1.02) brightness(.95);
  transform: scale(1.02);
}
.page .cover-overlay {
  position: absolute;
  inset: 0;
  /* Softer overlay so the cover isn’t too dark */
  background: linear-gradient(to bottom right, rgba(0,0,0,.18), rgba(0,0,0,.32));
}
.page .cover-content {
  position: relative;
  z-index: 1;
  padding: clamp(1rem, 3vw, 2rem);
  width: min(1100px, 92vw);
  text-align: center; /* center the title */
}
.page .cover-title {
  font-family: var(--ui);
  color: #fff;
  font-weight: 800;
  letter-spacing: .4px;
  line-height: 1.05;
  font-size: clamp(2rem, 5vw, 3.25rem);
  text-shadow: 0 3px 18px rgba(0,0,0,.28);
  margin: 0 0 .25rem;
}
.page .cover-authors {
  font-family: var(--body);
  color: rgba(255,255,255,.9);
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  margin: .25rem 0 1.25rem;
}
.page .cover-logos {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(0.075rem, 0.3vw, 0.15rem);
}
.page .cover-logo {
  height: clamp(2.8px, 0.64vw, 5.6px);
  width: auto;
  filter: drop-shadow(0 .5px 2px rgba(0,0,0,.18));
}
@media (max-width: 600px) {
  .page .cover-logo { height: clamp(2.4px, 0.84vw, 4.4px); }
}
/* Defensive: in case classes are stripped, ensure logos within cover-logos shrink */
.page .cover-logos img {
  height: clamp(18px, 2vw, 28px) !important;
  width: auto !important;
}
/* Simple table styling */
.page table {
  width: auto;
  max-width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 0;
  font-size: .85rem;
  table-layout: auto;
  font-variant-numeric: tabular-nums;
}
.page table th, .page table td {
  border: none;
  padding: .35rem .5rem;
  text-align: left;
  vertical-align: top;
  line-height: 1.3;
  word-break: break-word;
  overflow-wrap: anywhere;
  white-space: normal;
}
.page table thead th {
  background: color-mix(in oklab, var(--surface) 92%, var(--bg));
  border-bottom: 1.5px solid color-mix(in oklab, var(--border) 70%, transparent);
  font-weight: 700;
}
.page table tbody tr:nth-child(even) td {
  background: color-mix(in oklab, var(--surface) 88%, transparent);
}
.page table tfoot td { border-top: 1.5px solid color-mix(in oklab, var(--border) 70%, transparent); }
.page table caption { caption-side: top; text-align: center; font-style: italic; color: var(--muted); margin-bottom: .35rem; }
.page .tablenotes { color: var(--muted); font-size: .9em; }
/* Numeric alignment helpers */
.page table th.num, .page table td.num { text-align: right; }

/* Remove unintended borders around images and image-only tables */
.page img { border: 0; outline: 0; box-shadow: none; }
/* If a table is used just to position images, drop table cell borders */
.page table:has(img) { border: 0; }
.page table:has(img) th,
.page table:has(img) td { border: 0; }

.footer {
  border-top: 1px solid color-mix(in oklab, var(--border) 65%, transparent);
  background: color-mix(in oklab, var(--surface) 92%, transparent);
}
.footer-inner {
  max-width: 88ch;
  margin: 0 auto;
  padding: 1rem clamp(1rem, 3vw, 2rem);
  display: flex;
  gap: .5rem 1rem;
  flex-wrap: wrap;
  align-items: center;
  color: var(--muted);
  font-family: var(--ui);
}
.footer a { color: inherit; }
.footer .separator { opacity: .5; }

.loading { color: var(--muted); }

.pager { display: none; }

@media (max-width: 960px) {
  .masthead-inner { flex-direction: column; align-items: flex-start; gap: .6rem; }
  .masthead-left { width: 100%; }
  .reading-area { padding: 0 1rem 3.5rem; }
  .layout { grid-template-columns: 1fr; width: min(100%, 96vw); margin-top: 1.25rem; }
  .sidebar { position: fixed; transform: translateX(-100%); transition: transform .2s ease; width: 280px; z-index: 10; border-right: none; border-radius: 0 14px 14px 0; box-shadow: 0 20px 40px rgba(0,0,0,.25); top: 0; height: 100vh; }
  .sidebar.open { transform: translateX(0); }
  .content { grid-column: 1 / -1; }
  .page .chapter { scroll-margin-top: 80px; }
  .page .chapter + .chapter { margin-top: 2rem; padding-top: 1.6rem; }
  /* Tighter tables on mobile */
  .page table { font-size: .92rem; }
  .page table th, .page table td { padding: .3rem .4rem; line-height: 1.25; }

}

/* Solid fallback when no backdrop-filter */
@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
  .sidebar, .footer { backdrop-filter: none; -webkit-backdrop-filter: none; background: var(--surface); border-color: var(--border); }
}

/* Extra-small devices: tune typography for better fit */
@media (max-width: 600px) {
  .page h1 { font-size: 1.75rem; }
  .page h2 { font-size: 1.25rem; }
  .page h3 { font-size: 1.1rem; }
  .page table { font-size: 0.9rem; }
  .page table caption { font-size: 0.9em; }
  .page .tablenotes { font-size: 0.85em; }
  .page mjx-container { font-size: 0.82em !important; }
}

/* Mobile-first tweaks without affecting desktop layout */
@media (max-width: 720px) {
  body { font-size: 17px; }
  .page {
    padding: 1.25rem 1rem 6rem;
    box-shadow: 0 10px 28px rgba(0,0,0,0.08);
    margin: 0 auto;
  }
  .ask-chat {
    bottom: calc(env(safe-area-inset-bottom) + .85rem);
    width: 100%;
    justify-content: center;
  }
  .ask-pill {
    width: 88vw;
    min-width: 0;
    padding: .55rem .75rem;
    box-shadow: 0 10px 20px rgba(0,0,0,0.12);
  }
  .ask-chat.open .ask-pill {
    width: 88vw;
    transform: translateY(0);
  }
  .ask-pill input { font-size: .95rem; }
}

/* Hide sidebar by default on mobile; only show when toggled */
@media (max-width: 960px) {
  .sidebar { display: none; }
  .sidebar.open { display: block; }
}