@charset "UTF-8";
/* ==========================================================================
   Thai Educational E-Library - Interactive Reader Stylesheet
   Dual-Mode Engine: 3D Flip & Continuous Vertical Scroll
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Reader Container Layout & Visibility
   -------------------------------------------------------------------------- */
.reader-container {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary, #f8fafc);
  color: var(--text-primary, #1e293b);
  z-index: 500;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
}

/* Inactive/Hidden States */
.reader-container[hidden],
.reader-container.hidden {
  display: none !important;
}

/* Initial "Open Book" Overlay Button State */
.open-book {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 200;
  background-color: var(--accent, #2563eb);
  color: #ffffff;
  padding: 0.875rem 2rem;
  border-radius: var(--radius-full, 9999px);
  border: none;
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 1.125rem;
  font-weight: 600;
  box-shadow: 0 10px 25px -3px rgba(37, 99, 235, 0.4);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  transition: all 0.25s ease;
}

.open-book:hover {
  background-color: var(--accent-hover, #1d4ed8);
  transform: translate(-50%, -52%) scale(1.03);
  box-shadow: 0 15px 30px -3px rgba(37, 99, 235, 0.5);
}

.open-book:active {
  transform: translate(-50%, -48%) scale(0.98);
}

/* --------------------------------------------------------------------------
   2. Reader Header (Top Navigation & Info Bar)
   -------------------------------------------------------------------------- */
.reader-header {
  height: 56px;
  min-height: 56px;
  background-color: var(--bg-secondary, #ffffff);
  border-bottom: 1px solid var(--border-color, #e2e8f0);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
  z-index: 100;
  position: relative;
  gap: 0.75rem;
  box-shadow: var(--shadow-sm, 0 1px 2px 0 rgba(0, 0, 0, 0.05));
}

.reader-header-left {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-width: 0;
  flex: 1;
}

.reader-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.2s ease;
}

.reader-back-btn:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
  border-color: var(--accent, #2563eb);
}

/* TOC Toggle Button in Reader Header */
.reader-toc-btn,
.piyo-toc-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.45rem 0.85rem;
  height: 36px;
  width: auto;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.2s ease;
  line-height: 1;
}

.reader-toc-btn:hover,
.piyo-toc-btn:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
  border-color: var(--accent, #2563eb);
}

.reader-toc-btn .toc-icon,
.piyo-toc-btn .toc-icon {
  font-size: 1rem;
  line-height: 1;
}

.reader-toc-btn .toc-text,
.piyo-toc-btn .toc-text {
  font-size: 0.875rem;
  font-weight: 600;
  color: inherit;
  white-space: nowrap;
}

.reader-title-area {
  display: flex;
  flex-direction: column;
  min-width: 0;
  margin-left: 0.35rem;
  padding-left: 0.75rem;
  border-left: 1.5px solid var(--border-color, #e2e8f0);
}

.reader-book-title {
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.35;
}

.reader-chapter {
  font-size: 0.775rem;
  color: var(--text-secondary, #64748b);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.2;
}

.reader-header-right {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex-shrink: 0;
  flex-wrap: nowrap;
}

/* Mode Toggle Button (Flip / Scroll) */
.mode-toggle {
  display: inline-flex;
  align-items: center;
  background-color: var(--bg-primary, #f1f5f9);
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: var(--radius-full, 9999px);
  padding: 3px;
  gap: 2px;
}

.mode-toggle-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-full, 9999px);
  border: none;
  background: transparent;
  color: var(--text-secondary, #64748b);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.mode-toggle-btn.active {
  background-color: var(--bg-secondary, #ffffff);
  color: var(--accent, #2563eb);
  font-weight: 600;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

/* Fullscreen Button */
.btn-fullscreen,
.fullscreen-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.125rem;
  transition: all 0.2s ease;
}

.btn-fullscreen:hover,
.fullscreen-btn:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
  border-color: var(--accent, #2563eb);
}

/* --------------------------------------------------------------------------
   3. Viewport Shell & 3D Stage (Flip Mode)
   -------------------------------------------------------------------------- */
.viewport-shell {
  flex: 1;
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #f1f5f9;
  background-image: radial-gradient(#cbd5e1 1px, transparent 1px);
  background-size: 24px 24px;
}

/* Stage Area filling Viewport Shell */
.stage {
  width: 100%;
  height: 100%;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  touch-action: pan-x pan-y;
  cursor: grab;
}

.stage.is-panning {
  cursor: grabbing;
}

/* Paper Container with Real-World Physical Paper Effect */
.paper {
  position: relative;
  display: block;
  max-width: 96%;
  max-height: 94%;
  background-color: #ffffff;
  border-radius: 4px;
  box-shadow:
    0 12px 28px -4px rgba(0, 0, 0, 0.16),
    0 6px 14px -2px rgba(0, 0, 0, 0.08),
    -3px 0 10px rgba(0, 0, 0, 0.06);
  transition: width 0.2s cubic-bezier(0.16, 1, 0.3, 1), transform 0.15s ease-out;
  transform-origin: center center;
  perspective: 2400px;
}

/* Page Spine Effect */
.paper::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 16px;
  background: linear-gradient(to right, rgba(0, 0, 0, 0.18) 0%, rgba(255, 255, 255, 0.1) 40%, transparent 100%);
  pointer-events: none;
  z-index: 5;
}

.paper img {
  width: 100%;
  height: auto;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
  border-radius: 4px;
}

.paper img[src=""],
.paper img:not([src]) {
  opacity: 0;
  visibility: hidden;
}

/* Paper Loading Pulse / Shimmer */
.paper.loading {
  animation: paperShimmer 1.5s infinite;
  background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 50%, #f1f5f9 75%);
  background-size: 200% 100%;
}

@keyframes paperShimmer {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* Embedded PDF Viewer Box */
.pdf-embed-box {
  width: 100%;
  height: 82vh;
  min-height: 560px;
  max-height: 92vh;
  position: relative;
  background-color: #ffffff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
}

.pdf-reader-frame {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
  border-radius: 8px;
}

.paper.is-pdf-mode {
  width: min(94vw, 1000px) !important;
  max-height: 92vh;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.paper.is-pdf-mode::after {
  display: none !important;
}

[data-theme="dark"] .pdf-embed-box {
  background-color: #1e293b;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

/* PDF Real-Time Conversion Loading Box */
.pdf-loading-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 480px;
  width: 100%;
  padding: 2.5rem 1.5rem;
  text-align: center;
  background: var(--bg-card, #ffffff);
  border-radius: 12px;
}

.pdf-loading-spinner {
  width: 48px;
  height: 48px;
  border: 3.5px solid rgba(234, 88, 12, 0.15);
  border-top-color: #ea580c;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-bottom: 1.25rem;
}

.pdf-loading-text {
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  margin-bottom: 0.85rem;
}

.pdf-loading-bar-wrap {
  width: min(280px, 80%);
  height: 8px;
  background-color: rgba(234, 88, 12, 0.15);
  border-radius: 9999px;
  overflow: hidden;
  margin-bottom: 0.65rem;
}

.pdf-loading-bar {
  height: 100%;
  background: linear-gradient(90deg, #ea580c, #f97316);
  border-radius: 9999px;
  transition: width 0.25s ease;
}

.pdf-loading-sub {
  font-size: 0.825rem;
  color: var(--text-secondary, #64748b);
  font-weight: 400;
}

/* --------------------------------------------------------------------------
   4. 3D Page Turn Animation Layer
   -------------------------------------------------------------------------- */
.turn-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 25;
  perspective: 2000px;
  transform-style: preserve-3d;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  border-radius: 4px;
  overflow: hidden;
}

.turn-layer img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

/* Turn Animations */
.turn-layer.animating-forward {
  transform-origin: left center;
  animation: turnForward 0.45s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.turn-layer.animating-backward {
  transform-origin: right center;
  animation: turnBackward 0.45s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes turnForward {
  0% {
    transform: rotateY(0deg);
    opacity: 1;
    filter: drop-shadow(-4px 0 10px rgba(0, 0, 0, 0.25));
  }
  100% {
    transform: rotateY(-90deg);
    opacity: 0;
    filter: drop-shadow(-16px 0 24px rgba(0, 0, 0, 0.55));
  }
}

@keyframes turnBackward {
  0% {
    transform: rotateY(0deg);
    opacity: 1;
    filter: drop-shadow(4px 0 10px rgba(0, 0, 0, 0.25));
  }
  100% {
    transform: rotateY(90deg);
    opacity: 0;
    filter: drop-shadow(16px 0 24px rgba(0, 0, 0, 0.55));
  }
}

/* --------------------------------------------------------------------------
   5. Side-Turn Buttons (Left & Right Edges)
   -------------------------------------------------------------------------- */
.side-turn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 52px;
  height: 104px;
  background-color: rgba(15, 23, 42, 0.3);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 30;
  transition: all 0.25s ease;
  font-size: 1.5rem;
  user-select: none;
}

.side-turn:hover {
  background-color: rgba(15, 23, 42, 0.65);
  transform: translateY(-50%) scale(1.06);
}

.side-turn:active {
  transform: translateY(-50%) scale(0.96);
}

.side-turn.left {
  left: 0;
  border-top-right-radius: var(--radius-lg, 16px);
  border-bottom-right-radius: var(--radius-lg, 16px);
  border-left: none;
}

.side-turn.right {
  right: 0;
  border-top-left-radius: var(--radius-lg, 16px);
  border-bottom-left-radius: var(--radius-lg, 16px);
  border-right: none;
}

.side-turn:disabled,
.side-turn.disabled {
  opacity: 0.15;
  cursor: not-allowed;
  pointer-events: none;
}

/* --------------------------------------------------------------------------
   6. Continuous Vertical Scroll Mode (.mode-scroll)
   -------------------------------------------------------------------------- */
.reader-container.mode-scroll .viewport-shell {
  display: block;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  background-image: none;
}

.reader-container.mode-scroll .stage {
  display: block;
  width: 100%;
  height: auto;
  min-height: 100%;
  overflow: visible;
  padding: 2rem 1rem 4rem 1rem;
  cursor: default;
}

.reader-container.mode-scroll .side-turn {
  display: none !important;
}

.scroll-feed {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  width: 100%;
  max-width: 860px;
  margin: 0 auto;
}

.scroll-page-item {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  background-color: #ffffff;
  border-radius: var(--radius-md, 8px);
  box-shadow:
    0 4px 12px rgba(0, 0, 0, 0.08),
    0 1px 3px rgba(0, 0, 0, 0.05);
  overflow: hidden;
  position: relative;
  border-bottom: 2px solid var(--border-color, #e2e8f0);
}

.scroll-page-item img {
  width: 100%;
  height: auto;
  display: block;
  background-color: #f8fafc;
  min-height: 200px;
}

.scroll-page-badge {
  position: absolute;
  bottom: 0.75rem;
  right: 0.75rem;
  background-color: rgba(15, 23, 42, 0.75);
  color: #ffffff;
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.25rem 0.625rem;
  border-radius: var(--radius-full, 9999px);
  backdrop-filter: blur(4px);
  pointer-events: none;
}

/* --------------------------------------------------------------------------
   7. Table of Contents Sidebar (.toc-sidebar)
   -------------------------------------------------------------------------- */
.toc-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 320px;
  max-width: 85vw;
  height: 100%;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-right: 1px solid var(--border-color, #e2e8f0);
  box-shadow: var(--shadow-lg, 0 16px 32px rgba(0, 0, 0, 0.15));
  z-index: 600;
  display: flex;
  flex-direction: column;
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.toc-sidebar.open {
  transform: translateX(0);
}

.toc-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(2px);
  z-index: 590;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.toc-overlay.open {
  opacity: 1;
  visibility: visible;
}

.toc-sidebar .toc-header {
  height: 56px;
  padding: 0 1.25rem;
  border-bottom: 1px solid var(--border-color, #e2e8f0);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-shrink: 0;
}

.toc-title {
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.toc-close {
  background: none;
  border: none;
  color: var(--text-secondary, #64748b);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.toc-close:hover {
  color: var(--text-primary, #1e293b);
  background-color: var(--border-color, #e2e8f0);
}

.toc-sidebar nav {
  flex: 1;
  overflow-y: auto;
  padding: 0.875rem;
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
  scrollbar-width: thin;
}

.toc-sidebar a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.625rem 0.875rem;
  border-radius: var(--radius-md, 8px);
  color: var(--text-primary, #1e293b);
  text-decoration: none;
  font-size: 0.9375rem;
  transition: all 0.2s ease;
  line-height: 1.4;
}

.toc-sidebar a:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
}

.toc-sidebar a.active {
  background-color: var(--accent, #2563eb);
  color: #ffffff;
  font-weight: 600;
}

.toc-sidebar a.active .page-num {
  color: #ffffff;
  opacity: 0.9;
}

.toc-sidebar a .page-num {
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.8125rem;
  color: var(--text-secondary, #64748b);
  margin-left: 0.5rem;
  flex-shrink: 0;
}

/* Accordion Group (<details> and <summary>) */
.toc-sidebar details {
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: var(--radius-md, 8px);
  margin-bottom: 0.5rem;
  overflow: hidden;
}

.toc-sidebar summary {
  padding: 0.625rem 0.875rem;
  background-color: var(--bg-secondary, #ffffff);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  transition: background-color 0.2s ease;
}

.toc-sidebar summary::-webkit-details-marker {
  display: none;
}

.toc-sidebar summary::after {
  content: '▾';
  font-size: 0.875rem;
  transition: transform 0.2s ease;
}

.toc-sidebar details[open] summary::after {
  transform: rotate(180deg);
}

.toc-sidebar details[open] summary {
  border-bottom: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-primary, #f8fafc);
}

.toc-sidebar details .toc-sublist {
  padding: 0.375rem;
  background-color: var(--bg-secondary, #ffffff);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

/* --------------------------------------------------------------------------
   8. Reader Footer & Controls Bar
   -------------------------------------------------------------------------- */
.reader-footer {
  height: 60px;
  min-height: 60px;
  background-color: var(--bg-secondary, #ffffff);
  border-top: 1px solid var(--border-color, #e2e8f0);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  z-index: 40;
  gap: 1rem;
  position: relative;
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.03);
}

/* Zoom Control Group */
.zoom {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.zoom-btn {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm, 6px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.875rem;
  font-weight: 600;
  transition: all 0.2s ease;
}

.zoom-btn:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
  border-color: var(--accent, #2563eb);
}

.zoom-btn.fit {
  width: auto;
  padding: 0 0.625rem;
  font-size: 0.8125rem;
}

/* Paging Navigation Group */
.paging {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.paging-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.125rem;
  transition: all 0.2s ease;
}

.paging-btn:hover {
  background-color: var(--accent-light, #eff6ff);
  color: var(--accent, #2563eb);
  border-color: var(--accent, #2563eb);
}

.paging-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.paging input {
  width: 52px;
  height: 36px;
  text-align: center;
  padding: 0.25rem;
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: var(--radius-md, 8px);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-weight: 600;
  font-size: 0.9375rem;
  -moz-appearance: textfield;
}

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

.paging input:focus {
  outline: none;
  border-color: var(--accent, #2563eb);
  box-shadow: 0 0 0 3px var(--accent-light, #eff6ff);
}

.paging-total {
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.875rem;
  color: var(--text-secondary, #64748b);
  font-weight: 500;
  margin: 0 0.25rem;
}

/* Thin Reading Progress Bar */
.progress {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background-color: rgba(0, 0, 0, 0.08);
}

.progress i {
  display: block;
  height: 100%;
  width: 0%;
  background-color: var(--accent, #2563eb);
  transition: width 0.25s ease;
}

/* Reader Auxiliary Help Text */
.reader-help {
  font-size: 0.75rem;
  color: var(--text-secondary, #64748b);
  text-align: center;
  white-space: nowrap;
}

/* --------------------------------------------------------------------------
   9. Dark Mode Overrides ([data-theme="dark"])
   -------------------------------------------------------------------------- */
[data-theme="dark"] .reader-container {
  background-color: #0b1120;
}

[data-theme="dark"] .reader-header,
[data-theme="dark"] .reader-footer {
  background-color: #1e293b;
  border-color: #334155;
}

[data-theme="dark"] .reader-back-btn,
[data-theme="dark"] .reader-toc-btn,
[data-theme="dark"] .piyo-toc-btn,
[data-theme="dark"] .btn-fullscreen,
[data-theme="dark"] .fullscreen-btn,
[data-theme="dark"] .zoom-btn,
[data-theme="dark"] .paging-btn,
[data-theme="dark"] .paging input {
  background-color: #1e293b;
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .reader-toc-btn:hover,
[data-theme="dark"] .piyo-toc-btn:hover {
  background-color: #0f172a;
  border-color: #38bdf8;
  color: #38bdf8;
}

[data-theme="dark"] .reader-title-area {
  border-left-color: #334155;
}

[data-theme="dark"] .viewport-shell {
  background-color: #0b1120;
  background-image: radial-gradient(#334155 1px, transparent 1px);
}

[data-theme="dark"] .paper {
  background-color: #0f172a;
  box-shadow:
    0 16px 36px -4px rgba(0, 0, 0, 0.7),
    0 8px 18px -2px rgba(0, 0, 0, 0.5),
    -3px 0 12px rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] .scroll-page-item {
  background-color: #1e293b;
  border-bottom-color: #334155;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.5);
}

[data-theme="dark"] .scroll-page-item img {
  background-color: #0f172a;
}

[data-theme="dark"] .side-turn {
  background-color: rgba(30, 41, 59, 0.4);
  border-color: rgba(255, 255, 255, 0.1);
}

[data-theme="dark"] .side-turn:hover {
  background-color: rgba(30, 41, 59, 0.85);
}

[data-theme="dark"] .toc-sidebar {
  background-color: rgba(30, 41, 59, 0.95);
  border-right-color: #334155;
}

[data-theme="dark"] .toc-sidebar .toc-header {
  border-bottom-color: #334155;
}

[data-theme="dark"] .toc-sidebar summary {
  background-color: #1e293b;
}

[data-theme="dark"] .toc-sidebar details {
  border-color: #334155;
}

[data-theme="dark"] .toc-sidebar details[open] summary {
  background-color: #0f172a;
  border-bottom-color: #334155;
}

[data-theme="dark"] .toc-sidebar details .toc-sublist {
  background-color: #1e293b;
}

[data-theme="dark"] .mode-toggle {
  background-color: #0f172a;
  border-color: #334155;
}

[data-theme="dark"] .mode-toggle-btn.active {
  background-color: #1e293b;
  color: #38bdf8;
}

[data-theme="dark"] .progress {
  background-color: rgba(255, 255, 255, 0.1);
}

[data-theme="dark"] .progress i {
  background-color: #38bdf8;
}

/* --------------------------------------------------------------------------
   10. Mobile & Small Screen Responsive Adjustments
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
  .reader-book-title {
    max-width: 220px;
  }

  .reader-chapter {
    max-width: 180px;
  }

  .side-turn {
    width: 42px;
    height: 76px;
    font-size: 1.25rem;
  }

  .reader-help {
    display: none;
  }

  .zoom-btn.fit {
    padding: 0 0.4rem;
  }
}

@media (max-width: 640px) {
  .reader-header {
    padding: 0 0.5rem;
  }

  .reader-book-title {
    max-width: 140px;
    font-size: 0.875rem;
  }

  .reader-chapter {
    display: none;
  }

  .toc-sidebar {
    width: 100vw;
    max-width: 100vw;
  }

  .side-turn {
    width: 36px;
    height: 64px;
    font-size: 1.1rem;
    background-color: rgba(15, 23, 42, 0.2);
  }

  .reader-footer {
    padding: 0 0.5rem;
    gap: 0.5rem;
  }

  .zoom {
    display: none;
  }

  .paging-btn {
    width: 32px;
    height: 32px;
  }

  .paging input {
    width: 44px;
    height: 32px;
  }
}

/* --------------------------------------------------------------------------
   Reader Header Enhanced Controls (Cozy Piyo Unified Buttons & Popovers)
   -------------------------------------------------------------------------- */
.reader-header-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  height: 36px;
  min-height: 36px;
  padding: 0 0.75rem;
  border-radius: var(--radius-md, 8px);
  border: 1px solid var(--border-color, #e2e8f0);
  background-color: var(--bg-secondary, #ffffff);
  color: var(--text-primary, #1e293b);
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  transition: all 0.2s ease;
  line-height: 1;
  text-decoration: none;
  user-select: none;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.reader-header-btn:hover {
  background-color: var(--accent-light, #fff7ed);
  color: var(--accent, #ea580c);
  border-color: #ea580c;
}

.reader-header-btn.active {
  background-color: #fff7ed;
  color: #ea580c;
  border-color: #ea580c;
  font-weight: 600;
}

.reader-header-btn.active-playing {
  background-color: #ea580c !important;
  color: #ffffff !important;
  border-color: #ea580c !important;
  box-shadow: 0 2px 10px rgba(234, 88, 12, 0.45) !important;
  animation: pulseMusicBtn 1.8s infinite ease-in-out;
}

.header-speed-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: rgba(234, 88, 12, 0.12);
  color: #ea580c;
  border-radius: 9999px;
  padding: 2px 6px;
  font-size: 0.72rem;
  font-weight: 700;
  margin-left: 2px;
  line-height: 1.1;
  transition: all 0.15s ease;
}

.reader-header-btn.active-playing .header-speed-badge {
  background: rgba(255, 255, 255, 0.25);
  color: #ffffff;
}

@media (max-width: 1150px) {
  .reader-header-btn .btn-text {
    display: none;
  }
  .reader-header-btn {
    padding: 0 0.55rem;
  }
}

/* --------------------------------------------------------------------------
   Floating Popovers (BGM Studio & Auto-Flip Speed)
   -------------------------------------------------------------------------- */
.reader-popover-backdrop {
  position: fixed;
  inset: 0;
  top: 56px;
  z-index: 90;
  background: rgba(15, 23, 42, 0.18);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.reader-floating-popover {
  position: fixed;
  top: 62px;
  right: 12px;
  z-index: 120;
  width: 360px;
  max-width: calc(100vw - 24px);
  background: var(--bg-card, #ffffff);
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: 18px;
  box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.25), 0 0 0 1px rgba(0, 0, 0, 0.05);
  overflow: hidden;
  animation: popoverDropIn 0.22s cubic-bezier(0.16, 1, 0.3, 1);
  font-family: var(--font-body, 'Sarabun', sans-serif);
}

@keyframes popoverDropIn {
  from {
    opacity: 0;
    transform: translateY(-8px) scale(0.97);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.popover-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background: var(--bg-secondary, #f8fafc);
  border-bottom: 1px solid var(--border-color, #e2e8f0);
}

.popover-title-row {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary, #1e293b);
}

.popover-status-badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 9999px;
  background: #e2e8f0;
  color: #475569;
}

.popover-status-badge.active {
  background: #dcfce7;
  color: #15803d;
}

.btn-popover-close {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: #94a3b8;
  font-size: 0.85rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

.btn-popover-close:hover {
  background: rgba(0, 0, 0, 0.08);
  color: #1e293b;
}

.popover-body {
  padding: 0.85rem 1rem 1rem;
}

.popover-ctrl-row {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 0.75rem;
}

.btn-popover-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.85rem;
  border-radius: 10px;
  border: none;
  background: #ea580c;
  color: #ffffff;
  font-family: var(--font-heading, 'Prompt', sans-serif);
  font-size: 0.825rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 4px 10px rgba(234, 88, 12, 0.25);
  white-space: nowrap;
  transition: all 0.15s ease;
}

.btn-popover-primary:hover {
  background: #c2410c;
  transform: translateY(-1px);
}

.btn-popover-primary.active {
  background: #dc2626;
  box-shadow: 0 4px 10px rgba(220, 38, 38, 0.25);
}

.popover-volume-box {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex: 1;
  background: var(--bg-secondary, #f8fafc);
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: 10px;
  padding: 0.35rem 0.6rem;
}

.popover-range {
  flex: 1;
  height: 6px;
  accent-color: #ea580c;
  cursor: pointer;
}

.vol-val-pill {
  font-size: 0.75rem;
  font-weight: 700;
  color: #ea580c;
  min-width: 32px;
  text-align: right;
}

.popover-section-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary, #64748b);
  margin: 0.6rem 0 0.4rem;
}

/* Track list in popover */
.popover-tracks-list {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  max-height: 220px;
  overflow-y: auto;
  padding-right: 4px;
}

.popover-track-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--border-color, #e2e8f0);
  background: var(--bg-card, #ffffff);
  cursor: pointer;
  transition: all 0.15s ease;
}

.popover-track-item:hover {
  border-color: #ea580c;
  background: #fff7ed;
}

.popover-track-item.active {
  border-color: #ea580c;
  background: #fff7ed;
  font-weight: 600;
  box-shadow: 0 0 0 1px #ea580c;
}

.track-item-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.track-item-icon {
  font-size: 1.15rem;
}

.track-item-name {
  font-size: 0.85rem;
  color: var(--text-primary, #1e293b);
  font-weight: 600;
}

.track-item-genre {
  font-size: 0.7rem;
  color: #64748b;
  display: block;
}

.track-item-status {
  font-size: 0.75rem;
  color: #ea580c;
  font-weight: 700;
}

.btn-popover-link {
  width: 100%;
  margin-top: 0.65rem;
  padding: 0.4rem;
  border: none;
  background: transparent;
  color: var(--text-secondary, #64748b);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  text-align: center;
  border-radius: 8px;
  transition: all 0.15s ease;
}

.btn-popover-link:hover {
  color: #ea580c;
  background: rgba(234, 88, 12, 0.08);
}

/* Auto-flip Speed Popover Specifics */
.autoflip-current-badge {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
  color: var(--text-secondary, #64748b);
  background: var(--bg-secondary, #f8fafc);
  padding: 0.35rem 0.65rem;
  border-radius: 8px;
  border: 1px solid var(--border-color, #e2e8f0);
}

.autoflip-current-badge b {
  color: #ea580c;
  font-size: 0.95rem;
}

.speed-slider-box {
  background: var(--bg-secondary, #f8fafc);
  border: 1px solid var(--border-color, #e2e8f0);
  border-radius: 12px;
  padding: 0.75rem;
  margin-bottom: 0.75rem;
}

.speed-slider-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  margin-bottom: 0.45rem;
}

.speed-number-input {
  width: 52px;
  padding: 2px 6px;
  border-radius: 6px;
  border: 1px solid var(--border-color, #cbd5e1);
  text-align: center;
  font-weight: 700;
  color: #ea580c;
  font-size: 0.9rem;
}

.slider-ticks-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.68rem;
  color: var(--text-secondary, #94a3b8);
  margin-top: 3px;
}

.speed-presets-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.4rem;
}

.speed-preset-btn {
  padding: 0.4rem 0.2rem;
  border-radius: 8px;
  border: 1px solid var(--border-color, #cbd5e1);
  background: var(--bg-card, #ffffff);
  color: var(--text-primary, #1e293b);
  font-size: 0.76rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  text-align: center;
}

.speed-preset-btn:hover {
  border-color: #ea580c;
  color: #ea580c;
}

.speed-preset-btn.active {
  background: #ea580c;
  color: #ffffff;
  border-color: #ea580c;
  box-shadow: 0 2px 6px rgba(234, 88, 12, 0.35);
}

/* Dark mode overrides for popovers */
[data-theme="dark"] .reader-floating-popover {
  background: #1e293b;
  border-color: #334155;
  box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.6);
}

[data-theme="dark"] .popover-header {
  background: #0f172a;
  border-color: #334155;
}

[data-theme="dark"] .popover-title-row {
  color: #f8fafc;
}

[data-theme="dark"] .popover-status-badge {
  background: #334155;
  color: #94a3b8;
}

[data-theme="dark"] .popover-volume-box,
[data-theme="dark"] .speed-slider-box,
[data-theme="dark"] .autoflip-current-badge {
  background: #0f172a;
  border-color: #334155;
}

[data-theme="dark"] .popover-track-item,
[data-theme="dark"] .speed-preset-btn {
  background: #1e293b;
  border-color: #334155;
  color: #e2e8f0;
}

[data-theme="dark"] .popover-track-item.active {
  background: #443428;
  border-color: #ea580c;
}

[data-theme="dark"] #soundFxToggleInReader,
[data-theme="dark"] #btnReaderSettings {
  background-color: #1e293b;
  border-color: #334155;
  color: #f8fafc;
}