/* ============================================================
   reader.css - Document Reader Styles
   Understanding Machine Learning Study Guide
   ============================================================ */

/* ----- Top Bar ----- */

.top-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 56px;
  background: #fff;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
}

.back-link {
  font-size: 0.95rem;
  color: #1e3a8a;
  text-decoration: none;
  white-space: nowrap;
}

.back-link:hover {
  text-decoration: underline;
}

.top-bar-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: #202124;
  margin: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.page-counter {
  font-size: 0.9rem;
  color: #5f6368;
  white-space: nowrap;
}

/* ----- Page Display (Main Content) ----- */

.page-display {
  margin-top: 72px;
  margin-bottom: 100px;
  padding: 16px;
  display: flex;
  justify-content: center;
  transform-origin: top center;
  transition: transform 0.2s ease;
}

/* ----- Image View ----- */

.image-view {
  max-width: 900px;
  width: 100%;
  text-align: center;
}

.image-view img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
  border-radius: 4px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

/* ----- Text View ----- */

.text-view {
  max-width: 800px;
  width: 100%;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.1rem;
  line-height: 1.8;
  color: #202124;
}

.text-view h1,
.text-view h2,
.text-view h3 {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: #1a1a2e;
  margin-top: 1.5em;
}

.text-view h2 {
  font-size: 1.6rem;
  margin-top: 0;
  margin-bottom: 0.5em;
  padding-bottom: 0.4em;
  border-bottom: 2px solid #e8eaed;
}

.text-view h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5em;
}

.text-view h4 {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 1.05rem;
  color: #1a1a2e;
  margin-top: 1em;
  margin-bottom: 0.4em;
}

.text-view p {
  margin-bottom: 1em;
}

.text-view blockquote {
  border-left: 3px solid #dadce0;
  margin: 1em 0;
  padding: 0.5em 1em;
  color: #5f6368;
  background: #fafafa;
  border-radius: 0 6px 6px 0;
}

.text-view blockquote p {
  margin-bottom: 0.5em;
}

/* --- Page wrapper --- */
.text-view .page-content {
  padding: 0;
}

/* Empty page marker */
.text-view .empty-page {
  color: #9aa0a6;
  text-align: center;
  padding: 3em 1em;
  font-style: italic;
}

/* --- Definition boxes: green (core definitions and formal concepts) --- */
.text-view .definition-box {
  border-left: 4px solid #34a853;
  background: #f0faf3;
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1.02rem;
  line-height: 1.7;
}

.text-view .definition-box strong {
  color: #1e7e34;
}

/* --- Highlight boxes: blue (important data, tables, key findings) --- */
.text-view .highlight-box {
  border-left: 4px solid #1e3a8a;
  background: #eaf2fd;
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1.02rem;
  line-height: 1.7;
}

.text-view .highlight-box strong {
  color: #1e3a8a;
}

/* --- Figure boxes: yellow (figure descriptions) --- */
.text-view .figure-box {
  border-left: 4px solid #f9ab00;
  background: #fef9e7;
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1.02rem;
  line-height: 1.7;
}

.text-view .figure-box strong {
  color: #b77b00;
}

/* --- Theorem boxes: purple (mathematical theorems, lemmas, proofs) --- */
.text-view .theorem-box {
  border-left: 4px solid #8b5cf6;
  background: #f5f3ff;
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1.02rem;
  line-height: 1.7;
}

.text-view .theorem-box strong {
  color: #6d28d9;
}

/* --- Algorithm boxes: orange (algorithm descriptions, pseudocode) --- */
.text-view .algorithm-box {
  border-left: 4px solid #f97316;
  background: #fff7ed;
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 1.02rem;
  line-height: 1.7;
}

.text-view .algorithm-box strong {
  color: #c2410c;
}

.text-view .algorithm-box code {
  background: rgba(249, 115, 22, 0.1);
  color: #9a3412;
  padding: 0.15em 0.4em;
  border-radius: 3px;
  font-family: 'SF Mono', SFMono-Regular, ui-monospace, 'Cascadia Code', monospace;
  font-size: 0.92em;
}

/* --- Equations --- */
.text-view .equation {
  font-family: 'SF Mono', SFMono-Regular, ui-monospace, 'Cascadia Code', monospace;
  font-size: 1.1rem;
  text-align: center;
  margin: 0.5em 0;
  letter-spacing: 0.02em;
}

.text-view .equation-label {
  font-size: 0.9rem;
  color: #5f6368;
  text-align: center;
  display: block;
  margin-top: 0.25em;
}

/* --- Equation block (centered, with optional numbering) --- */
.text-view .equation-block {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin: 1.2em 0;
  padding: 12px 16px;
  background: #f8fafc;
  border-radius: 6px;
}

.text-view .equation-block .equation {
  margin: 0;
}

.text-view .equation-block .equation-number {
  font-family: 'SF Mono', SFMono-Regular, ui-monospace, 'Cascadia Code', monospace;
  font-size: 0.85rem;
  color: #94a3b8;
  flex-shrink: 0;
}

/* --- Inline math --- */
.text-view .math-inline {
  font-family: 'SF Mono', SFMono-Regular, ui-monospace, 'Cascadia Code', monospace;
  font-size: 0.95em;
  color: #1e3a8a;
  letter-spacing: 0.01em;
}

/* --- Chapter headings --- */
.text-view .chapter-heading {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 1.2rem;
  font-weight: 700;
  color: #1a1a2e;
  margin-top: 1.5em;
  margin-bottom: 0.2em;
}

.text-view .chapter-subtitle {
  font-size: 0.95rem;
  color: #5f6368;
  font-style: italic;
  margin-bottom: 1em;
}

/* --- Section headings (numbered sections within chapters) --- */
.text-view .section-heading {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 1.1rem;
  font-weight: 700;
  color: #0d9488;
  margin-top: 1.5em;
  margin-bottom: 0.4em;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* --- Commentary layer (analysis & digest) --- */
.text-view .commentary {
  background: #f8f9fa;
  border: 1px solid #e8eaed;
  border-radius: 12px;
  padding: 24px;
  margin-top: 2em;
}

.text-view .commentary > h3 {
  font-size: 1.15rem;
  color: #5f6368;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  margin-top: 0;
  margin-bottom: 1em;
  padding-bottom: 0.5em;
  border-bottom: 1px solid #e8eaed;
}

/* --- Commentary sub-sections --- */
.text-view .commentary-section {
  background: #fff;
  border-radius: 8px;
  padding: 16px 18px;
  margin-bottom: 12px;
  border: 1px solid #eef0f2;
}

.text-view .commentary-section:last-child {
  margin-bottom: 0;
}

.text-view .commentary-section h4 {
  font-size: 0.9rem;
  font-weight: 700;
  color: #1e3a8a;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 0;
  margin-bottom: 0.5em;
}

.text-view .commentary-section p {
  margin-bottom: 0;
  color: #3c4043;
  font-size: 1.02rem;
  line-height: 1.75;
}

/* Definition box inside commentary */
.text-view .commentary .definition-box {
  margin: 12px 0;
}

/* ----- Zoom Panel ----- */

.zoom-panel {
  position: fixed;
  left: 0;
  top: 50%;
  transform: translate(-90%, -50%);
  transition: transform 0.25s ease;
  z-index: 150;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 10px;
  background: rgba(32, 33, 36, 0.85);
  border-radius: 0 10px 10px 0;
  backdrop-filter: blur(6px);
}

.zoom-panel:hover {
  transform: translate(0, -50%);
}

.zoom-btn {
  background: transparent;
  color: #e8eaed;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 6px;
  padding: 6px 14px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}

.zoom-btn:hover {
  background: rgba(255, 255, 255, 0.15);
}

.zoom-btn.active {
  background: #1e3a8a;
  color: #fff;
  border-color: #1e3a8a;
}

.zoom-link {
  color: #93c5fd;
  font-size: 0.75rem;
  text-align: center;
  margin-top: 6px;
  text-decoration: none;
}

.zoom-link:hover {
  text-decoration: underline;
}

/* ----- Navigation ----- */

.page-nav {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 16px;
  z-index: 90;
  background: #fff;
  padding: 8px 20px;
  border-radius: 32px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.12);
}

.nav-btn {
  min-width: 48px;
  height: 48px;
  border: none;
  border-radius: 24px;
  background: #f1f3f4;
  color: #202124;
  font-size: 0.95rem;
  cursor: pointer;
  padding: 0 20px;
  transition: background 0.15s, box-shadow 0.15s;
}

.nav-btn:hover {
  background: #e8eaed;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
}

.nav-btn:active {
  background: #dadce0;
}

.page-input-wrap {
  display: flex;
  align-items: center;
}

.page-input {
  width: 80px;
  height: 40px;
  text-align: center;
  border: 1px solid #dadce0;
  border-radius: 20px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.15s;
  -moz-appearance: textfield;
}

.page-input::-webkit-inner-spin-button,
.page-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.page-input:focus {
  border-color: #1e3a8a;
}

/* ----- Progress Bar ----- */

.progress-bar-track {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: #e8eaed;
  z-index: 200;
}

.progress-bar-fill {
  height: 100%;
  background: #1e3a8a;
  width: 0;
  transition: width 0.3s ease;
}

/* ----- Context Menu FAB ----- */

.context-fab {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: none;
  background: #1e3a8a;
  color: #fff;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(30, 58, 138, 0.35);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, transform 0.15s;
}

.context-fab:hover {
  background: #1e40af;
  transform: scale(1.05);
}

/* ----- Context Menu Overlay ----- */

.context-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  z-index: 250;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.context-card {
  background: #fff;
  border-radius: 16px;
  padding: 28px 24px;
  width: 340px;
  max-width: 90vw;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.18);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.context-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.ctx-nav-btn {
  height: 40px;
  padding: 0 16px;
  border: none;
  border-radius: 20px;
  background: #f1f3f4;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s;
}

.ctx-nav-btn:hover {
  background: #e8eaed;
}

.ctx-page-label {
  font-size: 0.9rem;
  color: #5f6368;
}

.ctx-btn {
  height: 44px;
  border: none;
  border-radius: 10px;
  background: #1e3a8a;
  color: #fff;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background 0.15s;
}

.ctx-btn:hover {
  background: #1e40af;
}

.ctx-btn-close {
  background: #f1f3f4;
  color: #202124;
}

.ctx-btn-close:hover {
  background: #dadce0;
}

.ctx-search-wrap {
  position: relative;
}

.ctx-search-input {
  width: 100%;
  height: 44px;
  padding: 0 14px;
  border: 1px solid #dadce0;
  border-radius: 10px;
  font-size: 0.95rem;
  outline: none;
  box-sizing: border-box;
  transition: border-color 0.15s;
}

.ctx-search-input:focus {
  border-color: #1e3a8a;
}

.search-results {
  list-style: none;
  margin: 4px 0 0;
  padding: 0;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
  max-height: 240px;
  overflow-y: auto;
}

.search-results:empty {
  display: none;
}

.search-results li {
  padding: 10px 14px;
  cursor: pointer;
  font-size: 0.9rem;
  border-bottom: 1px solid #f1f3f4;
  transition: background 0.1s;
}

.search-results li:last-child {
  border-bottom: none;
}

.search-results li:hover {
  background: #f1f3f4;
}

.search-results .result-page {
  font-weight: 600;
  color: #1e3a8a;
  margin-right: 8px;
}

.ctx-link {
  display: block;
  text-align: center;
  color: #1e3a8a;
  text-decoration: none;
  font-size: 0.9rem;
}

.ctx-link:hover {
  text-decoration: underline;
}

/* ----- Responsive ----- */

@media (max-width: 768px) {
  .top-bar {
    padding: 0 12px;
    height: 48px;
  }

  .top-bar-title {
    font-size: 0.95rem;
  }

  .back-link {
    font-size: 0.85rem;
  }

  .page-counter {
    font-size: 0.8rem;
  }

  .page-display {
    margin-top: 60px;
    margin-bottom: 90px;
    padding: 8px;
  }

  .text-view {
    font-size: 1rem;
    line-height: 1.7;
  }

  .text-view h2 {
    font-size: 1.3rem;
  }

  .text-view .commentary {
    padding: 16px;
  }

  .text-view .commentary-section {
    padding: 12px 14px;
  }

  .text-view .definition-box,
  .text-view .highlight-box,
  .text-view .figure-box,
  .text-view .theorem-box,
  .text-view .algorithm-box {
    padding: 10px 14px;
  }

  .page-nav {
    padding: 6px 12px;
    gap: 10px;
  }

  .nav-btn {
    padding: 0 14px;
    font-size: 0.85rem;
  }

  .context-card {
    padding: 20px 16px;
    width: 300px;
  }

  .zoom-panel {
    padding: 8px 6px;
  }

  .zoom-btn {
    padding: 4px 10px;
    font-size: 0.75rem;
  }
}