@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@500;600;700&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ============================================================
   PDF-VIEWER STYLE BOOK
   - Gray canvas background (like Adobe Acrobat / Chrome PDF viewer)
   - White A4-width pages, drop shadow, page margins
   - Top navbar: Cover · Contents · Page navigation
   - Interactive Pyodide cells styled to look like book annotations,
     not Colab cells
   - Cover page uses a high-tech HUD aesthetic (neon accent + grid + corner brackets)
   ============================================================ */

:root {
  --canvas-bg: #4a4a4a;          /* PDF viewer dark gray canvas */
  --canvas-light: #6b6b6b;       /* lighter shade */
  --page-bg: #ffffff;            /* paper white */
  --page-ink: #1a1a1a;           /* text */
  --page-margin-color: #888;     /* light footer text */
  --book-accent: #2a3f5c;        /* navy blue accent for headings */
  --book-link: #1a4d80;          /* link blue */
  --book-rule: #d0d0d0;          /* hairline */
  --book-pull: #f6f6f6;          /* callout background */
  --book-code-bg: #f4f4f0;       /* code block, slight off-white */
  --book-code-border: #c0bca8;   /* warm border */
  --page-width: min(1100px, calc(100vw - 60px));  /* fit-to-width with side margins */
  --page-pad-y: 36px;            /* top/bottom margins inside page */
  --page-pad-x: 80px;             /* left/right margins inside page (book-like) */
}

html, body {
  background: var(--canvas-bg);
  color: var(--page-ink);
  font-family: "Georgia", "Charter", "Iowan Old Style", serif;
  font-size: 12pt;
  line-height: 1.55;
  letter-spacing: 0.01em;
  margin: 0;
  padding: 0;
}

/* Hide all sidebars and Quarto chrome */
.sidebar,
#quarto-sidebar,
#quarto-margin-sidebar,
.quarto-secondary-nav,
nav[role="doc-toc"],
.toc-active,
#TOC,
.page-columns aside,
.quarto-title-banner {
  display: none !important;
}

/* Hide auto-generated <h1 class="title"> (we have it in the page header) */
.quarto-title h1.title { display: none; }

/* Force single-column layout and wrap content in a "page" */
.page-columns,
.content,
main.content,
#quarto-document-content,
.quarto-grid-content,
.column-body {
  display: block !important;
  grid-template-columns: 1fr !important;
  max-width: none !important;
  margin: 0 !important;
  padding: 0 !important;
  background: transparent;
}

/* The page itself: white card that fits to viewport width */
main.content,
#quarto-document-content,
.quarto-grid-content {
  background: var(--page-bg) !important;
  width: var(--page-width);
  max-width: 1100px;
  margin: 30px auto !important;
  padding: var(--page-pad-y) var(--page-pad-x) !important;
  box-shadow: 0 8px 28px rgba(0,0,0,0.35), 0 1px 4px rgba(0,0,0,0.2);
  border-radius: 2px;
  min-height: 70vh;
  position: relative;
  box-sizing: border-box;
}

/* Page footer (chapter name + page number, like a real PDF page) */
main.content::after {
  content: attr(data-pagename) "";
  position: absolute;
  bottom: 8mm;
  left: 0;
  right: 0;
  text-align: center;
  font-family: "Georgia", serif;
  font-size: 9pt;
  color: var(--page-margin-color);
  letter-spacing: 0.05em;
}

/* Typography inside the page */
h1, h2, h3, h4 {
  font-family: "Georgia", serif;
  color: var(--book-accent);
  font-weight: 700;
  line-height: 1.25;
  page-break-after: avoid;
}
h1 {
  font-size: 22pt;
  margin: 0 0 0.4em 0;
  padding-bottom: 0.25em;
  border-bottom: 2px solid var(--book-accent);
}
h2 {
  font-size: 17pt;
  margin: 1.8em 0 0.5em 0;
  padding-bottom: 0.15em;
  border-bottom: 1px solid var(--book-rule);
}
h3 { font-size: 13pt; margin: 1.4em 0 0.4em 0; }
h4 { font-size: 11.5pt; margin: 1.2em 0 0.4em 0; font-style: italic; }

/* Section number prefix on H2/H3/H4 (e.g. "1.1", "2.1.3") */
.sec-num {
  display: inline-block;
  margin-right: 0.45em;
  color: var(--book-link);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  letter-spacing: 0.01em;
}
h2 > .sec-num { font-size: 0.92em; }
h3 > .sec-num { font-size: 0.92em; }
h4 > .sec-num { font-size: 0.92em; font-style: normal; }

p, li {
  font-family: "Georgia", serif;
  font-size: 12pt;
  line-height: 1.6;
  text-align: justify;
  hyphens: auto;
  -webkit-hyphens: auto;
}
li { text-align: left; }

a {
  color: var(--book-link);
  text-decoration: underline;
  text-decoration-color: rgba(26,77,128,0.4);
  text-underline-offset: 2px;
}
a:hover { text-decoration-color: var(--book-link); }

/* Code blocks — book annotation style, NOT Colab */
pre, .sourceCode {
  background: var(--book-code-bg) !important;
  border-left: 3px solid var(--book-accent) !important;
  border-right: none !important;
  border-top: none !important;
  border-bottom: none !important;
  border-radius: 0 !important;
  padding: 10pt 14pt !important;
  margin: 1em 0 !important;
  font-family: "SF Mono", "Menlo", "Consolas", monospace !important;
  font-size: 9.5pt !important;
  line-height: 1.45 !important;
  overflow-x: auto;
  box-shadow: none !important;
}
pre code, code {
  background: transparent !important;
  font-family: inherit !important;
  font-size: inherit !important;
  color: var(--page-ink);
}
:not(pre) > code {
  background: var(--book-code-bg) !important;
  padding: 0 4px !important;
  border-radius: 2px !important;
  border: 1px solid var(--book-rule);
  font-size: 0.92em !important;
}

/* Pyodide cells — keep functional but tone down the IDE look */
.exercise-cell, .cell-output, [class*="pyodide"] {
  background: var(--book-code-bg) !important;
  border: 1px solid var(--book-code-border) !important;
  border-left: 3px solid var(--book-accent) !important;
  border-radius: 2px !important;
  margin: 1em 0 !important;
  box-shadow: none !important;
}
button[class*="run"], .qpy-run, button[title*="Run"] {
  background: var(--book-accent) !important;
  color: white !important;
  border: none !important;
  border-radius: 2px !important;
  font-family: "Georgia", serif !important;
  font-weight: 600 !important;
  padding: 5px 12px !important;
  font-size: 10pt !important;
}
button[class*="run"]:hover { background: var(--book-link) !important; }
.CodeMirror {
  background: var(--book-code-bg) !important;
  font-family: "SF Mono", "Menlo", "Consolas", monospace !important;
  font-size: 9.5pt !important;
}

/* Callouts — paper annotation style */
.callout {
  border: none !important;
  border-left: 3px solid var(--book-accent) !important;
  background: var(--book-pull) !important;
  border-radius: 0 !important;
  margin: 1.2em 0 !important;
  padding: 8px 14px !important;
  box-shadow: none !important;
}
.callout-title {
  font-family: "Georgia", serif !important;
  color: var(--book-accent) !important;
  font-weight: 700;
  font-size: 11pt;
}
.callout-note { border-left-color: #4a6fa5 !important; }
.callout-tip  { border-left-color: #557a55 !important; }
.callout-important { border-left-color: #8b3a3a !important; }
.callout-warning { border-left-color: #a67b2c !important; }
.callout p, .callout li { font-size: 11pt; line-height: 1.55; }

/* Tables — book figure style */
table {
  border-collapse: collapse;
  margin: 1.2em auto;
  background: transparent;
  font-size: 11pt;
  width: 100%;
}
table th, table td {
  border: none;
  border-bottom: 1px solid var(--book-rule);
  padding: 6pt 10pt;
  text-align: left;
}
table thead th {
  border-bottom: 2px solid var(--book-accent);
  font-family: "Georgia", serif;
  font-weight: 700;
  color: var(--book-accent);
}

/* Blockquotes */
blockquote {
  border-left: 3px solid var(--book-rule);
  padding-left: 1.2em;
  color: #555;
  font-style: italic;
  margin: 1.3em 0;
}

/* Horizontal rules — minor section dividers */
hr {
  border: none;
  border-top: 1px solid var(--book-rule);
  margin: 1.6em auto;
  max-width: 60%;
}

/* ============================================================
   Top navbar — PDF viewer toolbar style
   ============================================================ */
.navbar {
  background: #2d2d2d !important;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3) !important;
  font-family: "Helvetica Neue", Arial, sans-serif !important;
  font-size: 13px !important;
  border-bottom: 1px solid #1a1a1a;
}
.navbar .navbar-nav .nav-link {
  color: #e0e0e0 !important;
  font-size: 13px !important;
  letter-spacing: 0.02em;
  opacity: 0.85;
}
.navbar .navbar-nav .nav-link:hover { opacity: 1; color: white !important; }
.navbar .navbar-nav .nav-link.active { opacity: 1; font-weight: 700; }
.navbar-brand { color: #e0e0e0 !important; font-size: 13px !important; }
.navbar .quarto-search input { background: #444 !important; color: #fff !important; border: 1px solid #555 !important; }

/* Footer — dark like PDF reader status bar */
.page-footer, footer.footer {
  background: #2d2d2d !important;
  color: #aaa !important;
  font-family: "Helvetica Neue", Arial, sans-serif !important;
  font-size: 11px !important;
  padding: 10px 0 !important;
  border-top: 1px solid #1a1a1a;
}
.page-footer a { color: #ccc !important; }

/* ============================================================
   Cover page — HIGH-TECH redesign (MediaBook: neon magenta accent)
   ============================================================ */
.book-cover {
  --cover-accent: #ff3df0;
  --cover-accent-2: #5cc8ff;
  --cover-accent-glow: rgba(255, 61, 240, 0.55);
  --cover-bg-1: #110416;
  --cover-bg-2: #2a0a3a;
  --cover-bg-3: #06020a;
  margin: 30px auto !important;
  padding: 90px 60px !important;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(255, 61, 240, 0.18) 0%, transparent 55%),
    radial-gradient(ellipse at 50% 100%, rgba(92, 200, 255, 0.12) 0%, transparent 60%),
    linear-gradient(135deg, var(--cover-bg-2) 0%, var(--cover-bg-1) 55%, var(--cover-bg-3) 100%);
  color: #ffe6fb;
  width: var(--page-width);
  max-width: 1100px;
  min-height: 82vh;
  box-shadow:
    0 0 0 1px rgba(255, 61, 240, 0.18) inset,
    0 0 80px rgba(255, 61, 240, 0.08) inset,
    0 14px 50px rgba(0, 0, 0, 0.7);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-sizing: border-box;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", sans-serif;
}
.book-cover::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 61, 240, 0.10) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 61, 240, 0.10) 1px, transparent 1px);
  background-size: 44px 44px;
  opacity: 0.55;
  -webkit-mask-image: radial-gradient(ellipse at center, black 30%, transparent 78%);
          mask-image: radial-gradient(ellipse at center, black 30%, transparent 78%);
  pointer-events: none;
}
.book-cover::after {
  content: "";
  position: absolute;
  inset: 26px;
  border: 1px solid rgba(255, 61, 240, 0.18);
  pointer-events: none;
  background:
    linear-gradient(to right,  var(--cover-accent), var(--cover-accent) 28px, transparent 28px) top left   / 28px 2px no-repeat,
    linear-gradient(to bottom, var(--cover-accent), var(--cover-accent) 28px, transparent 28px) top left   / 2px 28px no-repeat,
    linear-gradient(to left,   var(--cover-accent), var(--cover-accent) 28px, transparent 28px) top right  / 28px 2px no-repeat,
    linear-gradient(to bottom, var(--cover-accent), var(--cover-accent) 28px, transparent 28px) top right  / 2px 28px no-repeat,
    linear-gradient(to right,  var(--cover-accent), var(--cover-accent) 28px, transparent 28px) bottom left   / 28px 2px no-repeat,
    linear-gradient(to top,    var(--cover-accent), var(--cover-accent) 28px, transparent 28px) bottom left   / 2px 28px no-repeat,
    linear-gradient(to left,   var(--cover-accent), var(--cover-accent) 28px, transparent 28px) bottom right  / 28px 2px no-repeat,
    linear-gradient(to top,    var(--cover-accent), var(--cover-accent) 28px, transparent 28px) bottom right  / 2px 28px no-repeat;
  filter: drop-shadow(0 0 6px var(--cover-accent-glow));
}
.book-cover > * { position: relative; z-index: 1; }
.book-cover h1::before {
  content: "// TEXT ANALYTICS · ISOM 5640";
  display: block;
  font-family: "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 9.5pt;
  font-weight: 500;
  letter-spacing: 0.34em;
  color: var(--cover-accent);
  -webkit-text-fill-color: var(--cover-accent);
  background: none;
  text-shadow: 0 0 14px var(--cover-accent-glow);
  text-transform: uppercase;
  margin-bottom: 1.4em;
}
.book-cover h1 {
  font-family: "Space Grotesk", "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 52pt;
  color: #ffffff !important;
  border: none !important;
  font-weight: 700;
  margin: 0 0 0.5em 0;
  padding: 0 30pt !important;
  letter-spacing: -0.02em;
  line-height: 1.04;
  background: linear-gradient(180deg, #ffffff 0%, #ffc8f3 100%);
  -webkit-background-clip: text;
          background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow:
    0 0 18px var(--cover-accent-glow),
    0 0 38px rgba(255, 61, 240, 0.28);
}
.book-cover .subtitle {
  font-family: "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 10.5pt;
  font-style: normal;
  color: rgba(255, 230, 251, 0.72);
  margin: 0 30pt 2.4em 30pt;
  max-width: 580px;
  letter-spacing: 0.04em;
  line-height: 1.75;
}
.book-cover .author {
  font-family: "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 10pt;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  margin-top: 2.6em;
  color: rgba(255, 230, 251, 0.92);
}
.book-cover .pub-info {
  font-family: "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 8.5pt;
  margin-top: 0.55em;
  color: rgba(255, 230, 251, 0.5);
  letter-spacing: 0.14em;
  text-transform: uppercase;
}
.book-cover .author-site {
  color: var(--cover-accent);
  text-decoration: none;
  letter-spacing: 0.06em;
  border-bottom: 1px solid rgba(255, 61, 240, 0.4);
  padding-bottom: 1px;
  transition: all 0.2s;
}
.book-cover .author-site:hover {
  color: #ffffff;
  text-shadow: 0 0 10px var(--cover-accent-glow);
  border-bottom-color: #ffffff;
}
.open-book-btn {
  display: inline-block;
  margin-top: 3em;
  padding: 14px 44px;
  background: transparent;
  color: var(--cover-accent) !important;
  border: 1px solid var(--cover-accent);
  border-radius: 2px;
  font-family: "JetBrains Mono", "SF Mono", "Menlo", "Consolas", monospace;
  font-size: 10pt;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  text-decoration: none !important;
  font-weight: 600;
  position: relative;
  transition: all 0.25s ease;
  box-shadow:
    inset 0 0 0 1px transparent,
    0 0 0 rgba(255, 61, 240, 0);
}
.open-book-btn::before {
  content: "▸";
  margin-right: 12px;
  color: var(--cover-accent);
  text-shadow: 0 0 8px var(--cover-accent-glow);
}
.open-book-btn:hover {
  background: var(--cover-accent);
  color: #110416 !important;
  box-shadow:
    0 0 24px var(--cover-accent-glow),
    0 0 48px rgba(255, 61, 240, 0.28);
}
.open-book-btn:hover::before { color: #110416; text-shadow: none; }

/* ============================================================
   Contents page — cards inside an A4 page
   ============================================================ */
.toc-chapter {
  display: block;
  padding: 14px 20px;
  margin: 10px 0;
  border: 1px solid var(--book-rule);
  border-radius: 2px;
  background: #fafafa;
  text-decoration: none !important;
  transition: all 0.15s;
}
.toc-chapter:hover {
  background: #fff;
  border-color: var(--book-accent);
  transform: translateX(2px);
}
.toc-chapter .ch-num {
  display: inline-block;
  font-family: "Georgia", serif;
  font-size: 9pt;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--book-link);
  font-weight: 700;
}
.toc-chapter .ch-title {
  display: block;
  font-family: "Georgia", serif;
  font-size: 15pt;
  color: var(--book-accent);
  font-weight: 700;
  margin: 2px 0 4px 0;
}
.toc-chapter .ch-desc {
  font-family: "Georgia", serif;
  font-size: 10.5pt;
  color: #555;
  margin: 0;
  text-decoration: none;
}

/* ============================================================
   Chapter prev/next footer (on each chapter page)
   ============================================================ */
.chapter-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin: 3em 0 2em 0;
  padding-top: 1.5em;
  border-top: 1px solid var(--book-rule);
}
.chapter-nav a {
  flex: 1;
  padding: 12px 18px;
  border: 1px solid var(--book-rule);
  border-radius: 2px;
  background: #fafafa;
  text-decoration: none !important;
  font-family: "Georgia", serif;
  color: var(--page-ink);
  display: flex;
  flex-direction: column;
  transition: all 0.15s;
}
.chapter-nav a.next { text-align: right; align-items: flex-end; }
.chapter-nav a.prev { text-align: left; }
.chapter-nav a:hover { background: white; border-color: var(--book-accent); }
.chapter-nav .label {
  font-size: 8.5pt;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--book-link);
  font-weight: 700;
}
.chapter-nav .title {
  font-size: 11pt;
  color: var(--book-accent);
  font-weight: 700;
  margin-top: 2px;
}

/* Mobile — let A4 width gracefully shrink */
@media (max-width: 800px) {
  main.content, .book-cover {
    margin: 16px auto !important;
    padding: 18px 22px !important;
    width: calc(100% - 32px) !important;
  }
  html, body { font-size: 11pt; }
  .book-cover h1 { font-size: 32pt; padding: 0 16pt !important; }
  .book-cover .subtitle { font-size: 13pt; }
  .chapter-nav { flex-direction: column; }
}

/* ============================================================
   A4 PAGINATED VIEW (default)
   - JS in _includes/paginate.html wraps each ## H2 section into a
     .pdf-page div. Each .pdf-page is sized like a single A4 sheet.
   - main.content becomes a transparent container that just spaces
     the pages on the gray canvas.
   - Continuous mode (body.no-paginate) reverts to the original
     "one long white card" behavior.
   ============================================================ */

/* When paginated, the container is transparent — pages provide their own paper */
body:not(.no-paginate) main.content[data-paginated="1"],
body:not(.no-paginate) #quarto-document-content[data-paginated="1"] {
  background: transparent !important;
  box-shadow: none !important;
  padding: 0 !important;
  width: auto !important;
  max-width: none !important;
  margin: 0 auto !important;
  min-height: 0 !important;
}
body:not(.no-paginate) main.content[data-paginated="1"]::after,
body:not(.no-paginate) #quarto-document-content[data-paginated="1"]::after {
  content: none;
}

/* Each .pdf-page is a single A4-shaped white card.
   Pages have a min-height of A4 so short sections still look like
   a real PDF page; longer sections (e.g. after a Pyodide cell runs
   and produces output) extend the card naturally. The footer is
   pinned to the bottom of each card regardless of height. */
.pdf-page {
  background: var(--page-bg);
  width: var(--page-width);
  max-width: 1100px;
  /* A4 aspect ratio = 1 : 1.414 (210 × 297 mm). */
  min-height: calc(var(--page-width) * 1.414);
  /* Vertical gap between pages on the gray canvas. Large enough
     that shadows from adjacent pages don't bleed together. */
  margin: 0 auto 56px !important;
  padding: var(--page-pad-y) var(--page-pad-x) calc(var(--page-pad-y) + 28px);
  /* Tighter, less-blurry shadow so it stays under the page card
     instead of filling the gap between pages. */
  box-shadow: 0 4px 10px rgba(0,0,0,0.28),
              0 1px 2px rgba(0,0,0,0.22);
  border-radius: 2px;
  position: relative;
  box-sizing: border-box;
  page-break-after: always;
  break-after: page;
  /* Subtle hairline so the page edge stays crisp on the gray canvas */
  outline: 1px solid rgba(0,0,0,0.08);
}
.pdf-page:first-child { margin-top: 30px !important; }
.pdf-page:last-child  { margin-bottom: 80px !important; }

/* Page footer at the bottom of each .pdf-page */
.pdf-page-footer {
  position: absolute;
  bottom: 10mm;
  left: var(--page-pad-x);
  right: var(--page-pad-x);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-family: "Georgia", serif;
  font-size: 9pt;
  color: var(--page-margin-color);
  border-top: 1px solid var(--book-rule);
  padding-top: 6px;
  letter-spacing: 0.04em;
}
.pdf-page-footer .pdf-page-chapter {
  font-style: italic;
  max-width: 70%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.pdf-page-footer .pdf-page-num {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}

/* The first .pdf-page in a chapter holds the H1 title — give it
   a touch more breathing room at the top, like a chapter opener */
.pdf-page:first-child h1.title,
.pdf-page:first-child > h1:first-child {
  margin-top: 0.2em;
}

/* Hide the .pdf-page footer (and treat as single page) when user picks continuous */
body.no-paginate .pdf-page {
  box-shadow: none !important;
  margin: 0 !important;
  padding: 0 !important;
  min-height: 0 !important;
  width: auto !important;
  background: transparent !important;
  break-after: auto;
  page-break-after: auto;
}
body.no-paginate .pdf-page-footer { display: none !important; }

/* ============================================================
   VIEW MODE TOGGLE (Paginated / Continuous)
   ============================================================ */
.view-toggle {
  position: fixed;
  top: 70px;
  right: 16px;
  z-index: 1000;
  background: rgba(45,45,45,0.95);
  color: #e0e0e0;
  border: 1px solid #555;
  border-radius: 18px;
  padding: 6px 12px;
  display: flex;
  gap: 0;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 11px;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
  user-select: none;
  overflow: hidden;
}
.view-toggle .opt {
  padding: 4px 10px;
  border-radius: 14px;
  letter-spacing: 0.03em;
  transition: background 0.15s, color 0.15s;
}
.view-toggle .opt.active {
  background: var(--book-accent);
  color: #fff;
  font-weight: 600;
}
.view-toggle .opt:not(.active):hover { color: #fff; }

/* Don't show the toggle on cover/contents pages */
body.book-cover-host .view-toggle { display: none; }

/* ============================================================
   Mobile — pagination still works, just narrower */
@media (max-width: 800px) {
  .pdf-page {
    margin: 0 auto 32px !important;
    padding: 18px 22px 50px !important;
    min-height: calc(var(--page-width) * 1.414);
    width: calc(100% - 32px) !important;
  }
  .pdf-page-footer {
    left: 22px;
    right: 22px;
    bottom: 14px;
    font-size: 8.5pt;
  }
  .view-toggle { top: 60px; right: 8px; font-size: 10px; padding: 4px 8px; }
}

/* ============================================================
   FEATURE 1 — Predict-then-reveal output cells
   ============================================================ */
.predict-output {
  margin: 1.2em 0;
}
.predict-output .predict-wrap {
  border: 1px dashed var(--book-accent);
  border-radius: 4px;
  background: #fafbfd;
  padding: 8px 10px;
  margin-top: -6px;
}
.predict-gate {
  display: block;
  width: 100%;
  padding: 14px 16px;
  background: linear-gradient(135deg, #ecf0f7 0%, #d6dff0 100%);
  border: 1px solid var(--book-accent);
  border-radius: 4px;
  font-family: "Georgia", serif;
  font-size: 11pt;
  font-style: italic;
  color: var(--book-accent);
  cursor: pointer;
  text-align: center;
  letter-spacing: 0.02em;
  transition: background 0.15s, transform 0.05s;
}
.predict-gate:hover { background: linear-gradient(135deg, #dde6f3 0%, #bccae4 100%); }
.predict-gate:active { transform: scale(0.99); }
.predict-gate.revealed {
  background: #f4f4f0;
  font-size: 9.5pt;
  font-style: normal;
  padding: 6px 12px;
  color: #555;
}
.predict-hidden { display: none !important; }

/* ============================================================
   FEATURE 2 — Spaced-repetition flashcards
   ============================================================ */
.flashcard {
  margin: 1.4em 0;
  padding: 14px 18px 12px;
  background: linear-gradient(180deg, #ffffff 0%, #f7f8fc 100%);
  border: 1px solid var(--book-rule);
  border-left: 3px solid var(--book-accent);
  border-radius: 4px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
  font-family: "Georgia", serif;
}
.flashcard .fc-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 9.5pt;
  margin-bottom: 6px;
  color: #777;
}
.flashcard .fc-tag {
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--book-accent);
}
.flashcard .fc-meta { font-style: italic; }
.flashcard .fc-q {
  font-size: 11.5pt;
  margin: 4px 0 10px 0;
  line-height: 1.5;
}
.flashcard .fc-show {
  background: var(--book-accent);
  color: white;
  border: none;
  padding: 7px 16px;
  border-radius: 3px;
  font-family: "Georgia", serif;
  font-size: 10.5pt;
  cursor: pointer;
  transition: background 0.15s;
}
.flashcard .fc-show:hover { background: var(--book-link); }
.flashcard .fc-a {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px dashed var(--book-rule);
}
.flashcard .fc-a-body {
  font-size: 11pt;
  line-height: 1.55;
  margin-bottom: 10px;
  color: #1a1a1a;
}
.flashcard .fc-a-body code {
  background: var(--book-code-bg);
  padding: 0 4px;
  border-radius: 2px;
  font-size: 0.92em;
}
.flashcard .fc-rate {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}
.flashcard .fc-btn {
  flex: 1;
  min-width: 70px;
  padding: 7px 10px;
  border: 1px solid;
  border-radius: 3px;
  font-family: "Helvetica Neue", Arial, sans-serif;
  font-size: 10pt;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.12s;
  background: white;
}
.flashcard .fc-btn.again { color: #c0392b; border-color: #c0392b; }
.flashcard .fc-btn.hard  { color: #a67b2c; border-color: #a67b2c; }
.flashcard .fc-btn.good  { color: #2a7a4a; border-color: #2a7a4a; }
.flashcard .fc-btn.easy  { color: #4a6fa5; border-color: #4a6fa5; }
.flashcard .fc-btn:hover { color: white; }
.flashcard .fc-btn.again:hover { background: #c0392b; }
.flashcard .fc-btn.hard:hover  { background: #a67b2c; }
.flashcard .fc-btn.good:hover  { background: #2a7a4a; }
.flashcard .fc-btn.easy:hover  { background: #4a6fa5; }

/* ============================================================
   FEATURE 3 — Parameter sliders
   ============================================================ */
.param-slider {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 1em 0;
  padding: 10px 14px;
  background: #f4f7fc;
  border: 1px solid var(--book-rule);
  border-radius: 4px;
  font-family: "Georgia", serif;
}
.param-slider label {
  font-size: 11pt;
  color: var(--book-accent);
  font-weight: 700;
  white-space: nowrap;
}
.param-slider input[type="range"] {
  flex: 1;
  accent-color: var(--book-accent);
}
.param-slider .value {
  font-family: "SF Mono", monospace;
  font-weight: 700;
  color: var(--book-link);
  font-size: 11pt;
  min-width: 3em;
  display: inline-block;
  text-align: right;
}
.param-slider .hint {
  font-size: 9.5pt;
  color: #777;
  font-style: italic;
  flex-shrink: 0;
}

/* ============================================================
   FEATURE 4 — Debug-yourself exercise wrapper
   ============================================================ */
.debug-yourself {
  border-left: 3px solid #c0392b;
  background: linear-gradient(180deg, #fdf4f3 0%, #ffffff 60%);
  padding: 12px 16px;
  margin: 1.2em 0;
  border-radius: 0 4px 4px 0;
}
.debug-yourself::before {
  content: "🔧 Debug yourself";
  display: block;
  font-family: "Georgia", serif;
  font-weight: 700;
  color: #c0392b;
  font-size: 10pt;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 6px;
}

/* Print = real PDF export looks good too */
@media print {
  body { background: white; }
  main.content, .book-cover { box-shadow: none !important; margin: 0 !important; }
  .pdf-page {
    box-shadow: none !important;
    margin: 0 !important;
    border-radius: 0;
    page-break-after: always;
  }
  .navbar, .page-footer, .view-toggle { display: none !important; }
}