/* MCQs in Operative Dentistry - Custom Stylesheet */
:root {
  --primary: #0d9488;
  --primary-hover: #0f766e;
  --primary-light: #ccfbf1;
  --primary-dark: #115e59;
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --success: #10b981;
  --success-bg: #d1fae5;
  --error: #ef4444;
  --error-bg: #fee2e2;
  --warning: #f59e0b;
  --warning-bg: #fef3c7;
  --accent: #0d9488;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --radius: 0.75rem;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-arabic: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

[data-theme="dark"] {
  --bg-main: #0f172a;
  --bg-card: #1e293b;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --primary-light: #134e4a;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

[dir="rtl"] {
  font-family: var(--font-arabic);
}

/* 🛡️ Strict Content Protection Shield - No Text Selection / No Touch Callout */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
  user-select: none !important;
  -webkit-user-select: none !important;
  -moz-user-select: none !important;
  -ms-user-select: none !important;
  -webkit-touch-callout: none !important;
  -webkit-user-drag: none !important;
}

input, textarea {
  user-select: text !important;
  -webkit-user-select: text !important;
}

body {
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Anti-Print & Screenshot Protection Rules */
@media print {
  html, body, #app-root {
    display: none !important;
    visibility: hidden !important;
    opacity: 0 !important;
  }
}

/* Fullscreen Immersive Intro Video Overlay */
.intro-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: #000000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  transition: opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1), transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

.intro-overlay.hidden {
  opacity: 0;
  pointer-events: none;
  transform: scale(1.04);
}

.intro-video-box {
  width: 100vw;
  height: 100vh;
  max-width: 100%;
  max-height: 100%;
  background: #000;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.intro-video-box video {
  width: 100%;
  height: 100%;
  object-fit: contain;
  background: #000;
}

.skip-intro-btn {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 30;
  background: rgba(13, 148, 136, 0.85);
  backdrop-filter: blur(8px);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.4);
  padding: 0.65rem 1.4rem;
  border-radius: 9999px;
  font-size: 0.9rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 4px 15px rgba(0,0,0,0.4);
  transition: all 0.25s ease;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

[dir="rtl"] .skip-intro-btn {
  right: auto;
  left: 1.5rem;
}

.skip-intro-btn:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(13, 148, 136, 0.6);
}

/* Header & Navbar */
.navbar {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--card-shadow);
  animation: navbarFade 0.6s ease-out;
}

@keyframes navbarFade {
  0% { opacity: 0; transform: translateY(-15px); }
  100% { opacity: 1; transform: translateY(0); }
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.brand-logo-img {
  width: 44px;
  height: 44px;
  border-radius: 0.5rem;
  object-fit: cover;
  border: 2px solid var(--primary);
  box-shadow: 0 2px 5px rgba(13, 148, 136, 0.3);
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.2;
}

.brand-subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.security-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: #059669;
  background: #d1fae5;
  padding: 0.25rem 0.6rem;
  border-radius: 9999px;
  border: 1px solid #a7f3d0;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: 0.5rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
  text-decoration: none;
  touch-action: manipulation;
}

.btn-primary {
  background-color: var(--primary);
  color: white;
}
.btn-primary:hover {
  background-color: var(--primary-hover);
}

.btn-secondary {
  background-color: transparent;
  border-color: var(--border-color);
  color: var(--text-main);
}
.btn-secondary:hover {
  background-color: rgba(0, 0, 0, 0.05);
}

.btn-outline {
  border-color: var(--primary);
  color: var(--primary);
  background: transparent;
}
.btn-outline:hover {
  background-color: var(--primary);
  color: white;
}

.btn-sm {
  padding: 0.3rem 0.65rem;
  font-size: 0.8rem;
}

.btn-icon {
  padding: 0.5rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-main);
}

.nav-tabs {
  display: flex;
  background: rgba(0, 0, 0, 0.04);
  padding: 0.25rem;
  border-radius: 0.5rem;
  gap: 0.25rem;
}

[data-theme="dark"] .nav-tabs {
  background: rgba(255, 255, 255, 0.05);
}

.tab-btn {
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
  font-weight: 600;
  border: none;
  border-radius: 0.375rem;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn.active {
  background: var(--bg-card);
  color: var(--primary);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

/* Layout Containers */
.main-content {
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
  flex: 1;
}

/* Book Mint / Teal Hero Card */
.hero-card {
  position: relative;
  background: linear-gradient(135deg, #0d9488 0%, #115e59 100%);
  color: white;
  border-radius: 1.25rem;
  padding: 2.5rem 2rem;
  margin-bottom: 2.5rem;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2.5rem;
  align-items: center;
  box-shadow: 0 20px 30px -10px rgba(13, 148, 136, 0.25), 0 0 0 1px rgba(255, 255, 255, 0.15);
  overflow: hidden;
  animation: heroEntrance 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.hero-card::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.15) 0%, transparent 60%);
  animation: pulseLight 8s infinite alternate ease-in-out;
  pointer-events: none;
}

@keyframes heroEntrance {
  0% { opacity: 0; transform: translateY(20px); }
  100% { opacity: 1; transform: translateY(0); }
}

@keyframes pulseLight {
  0% { transform: scale(0.9) rotate(0deg); opacity: 0.3; }
  100% { transform: scale(1.1) rotate(10deg); opacity: 0.7; }
}

.hero-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.22);
  backdrop-filter: blur(8px);
  padding: 0.3rem 0.85rem;
  border-radius: 9999px;
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.hero-title {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 0.5rem;
  text-shadow: 0 2px 4px rgba(0,0,0,0.15);
}

.hero-subtitle {
  font-size: 1.05rem;
  opacity: 0.95;
  margin-bottom: 1.5rem;
  max-width: 650px;
}

.hero-stats {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 800;
  color: #ccfbf1;
}

.stat-label {
  font-size: 0.75rem;
  opacity: 0.9;
}

.hero-cover {
  width: 170px;
  height: 220px;
  background: #ffffff;
  border-radius: 0.85rem;
  box-shadow: 0 15px 30px rgba(0,0,0,0.3), 0 0 15px rgba(13, 148, 136, 0.4);
  overflow: hidden;
  border: 3px solid rgba(255,255,255,0.5);
  transform: perspective(1000px) rotateY(-8deg) rotateX(4deg);
  transition: all 0.4s ease;
}

.hero-cover:hover {
  transform: perspective(1000px) rotateY(0deg) rotateX(0deg) scale(1.03);
}

.hero-cover-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Grid & Animated Chapter Cards */
.grid-chapters {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.chapter-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  box-shadow: var(--card-shadow);
  position: relative;
  overflow: hidden;
  animation: cardPop 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
}

@keyframes cardPop {
  0% { opacity: 0; transform: translateY(30px) scale(0.95); }
  100% { opacity: 1; transform: translateY(0) scale(1); }
}

.chapter-card:nth-child(1) { animation-delay: 0.05s; }
.chapter-card:nth-child(2) { animation-delay: 0.1s; }
.chapter-card:nth-child(3) { animation-delay: 0.15s; }
.chapter-card:nth-child(4) { animation-delay: 0.2s; }
.chapter-card:nth-child(5) { animation-delay: 0.25s; }
.chapter-card:nth-child(6) { animation-delay: 0.3s; }
.chapter-card:nth-child(7) { animation-delay: 0.35s; }
.chapter-card:nth-child(8) { animation-delay: 0.4s; }
.chapter-card:nth-child(9) { animation-delay: 0.45s; }

.chapter-card:hover {
  transform: translateY(-5px) scale(1.01);
  border-color: var(--primary);
  box-shadow: 0 15px 30px -10px rgba(13, 148, 136, 0.2);
}

.chapter-card.featured {
  border: 2px solid var(--primary);
}

.chapter-badge-loaded {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: var(--success-bg);
  color: var(--success);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  border-radius: 0.375rem;
}

[dir="rtl"] .chapter-badge-loaded {
  right: auto;
  left: 0.75rem;
}

.chapter-num {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.chapter-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  line-height: 1.3;
}

.chapter-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border-color);
}

/* Question View & Protection Overlay Mask */
.quiz-container {
  max-width: 860px;
  margin: 0 auto;
  animation: heroEntrance 0.5s ease-out;
}

.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 1rem;
  padding: 1.75rem;
  box-shadow: var(--card-shadow);
  margin-bottom: 1.5rem;
  position: relative;
}

.question-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.topic-tag {
  background: var(--primary-light);
  color: var(--primary-dark);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.625rem;
  border-radius: 0.375rem;
}

[data-theme="dark"] .topic-tag {
  color: #5eead4;
}

.page-ref {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
}

.question-text {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.option-btn {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  width: 100%;
  padding: 1rem 1.25rem;
  background: var(--bg-main);
  border: 2px solid var(--border-color);
  border-radius: 0.75rem;
  cursor: pointer;
  text-align: left;
  font-size: 0.95rem;
  color: var(--text-main);
  transition: all 0.2s ease;
}

[dir="rtl"] .option-btn {
  text-align: right;
}

.option-btn:hover:not(.disabled) {
  border-color: var(--primary);
  background: rgba(13, 148, 136, 0.05);
}

.option-letter {
  width: 1.75rem;
  height: 1.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  flex-shrink: 0;
  color: var(--text-muted);
}

.option-btn.selected {
  border-color: var(--primary);
  background: rgba(13, 148, 136, 0.08);
}

.option-btn.correct {
  border-color: var(--success);
  background: var(--success-bg);
  color: #065f46;
}

.option-btn.correct .option-letter {
  background: var(--success);
  color: white;
  border-color: var(--success);
}

.option-btn.incorrect {
  border-color: var(--error);
  background: var(--error-bg);
  color: #991b1b;
}

.option-btn.incorrect .option-letter {
  background: var(--error);
  color: white;
  border-color: var(--error);
}

.explanation-box {
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  padding: 1rem 1.25rem;
  border-radius: 0.5rem;
  margin-top: 1.25rem;
  font-size: 0.9rem;
}

[dir="rtl"] .explanation-box {
  border-left: none;
  border-right: 4px solid var(--primary);
}

.explanation-title {
  font-weight: 700;
  color: var(--primary-dark);
  margin-bottom: 0.25rem;
}

[data-theme="dark"] .explanation-title {
  color: #5eead4;
}

/* Controls & Pagination */
.quiz-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.question-select {
  padding: 0.5rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  color: var(--text-main);
  font-size: 0.9rem;
}

/* Score Card */
.score-card {
  background: var(--bg-card);
  border-radius: 1rem;
  border: 1px solid var(--border-color);
  padding: 2rem;
  text-align: center;
  box-shadow: var(--card-shadow);
}

.score-circle {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: conic-gradient(var(--primary) var(--percentage), var(--border-color) 0deg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 1.5rem auto;
  position: relative;
}

.score-inner {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
}

/* Table View */
.table-responsive {
  overflow-x: auto;
  background: var(--bg-card);
  border-radius: 0.75rem;
  border: 1px solid var(--border-color);
  box-shadow: var(--card-shadow);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

[dir="rtl"] .data-table {
  text-align: right;
}

.data-table th, .data-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
}

.data-table th {
  background: var(--bg-main);
  font-weight: 700;
  color: var(--text-muted);
}

.ans-badge {
  display: inline-block;
  width: 1.8rem;
  height: 1.8rem;
  line-height: 1.8rem;
  text-align: center;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
}

/* Flashcards */
.flashcard-wrapper {
  perspective: 1000px;
  width: 100%;
  max-width: 600px;
  height: 340px;
  margin: 2rem auto;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  transform-style: preserve-3d;
}

.flashcard-wrapper.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 1rem;
  border: 1px solid var(--border-color);
  background: var(--bg-card);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: var(--card-shadow);
}

.flashcard-back {
  transform: rotateY(180deg);
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--primary-light) 100%);
}

/* Footer */
footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border-color);
  padding: 1.5rem 1.25rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: auto;
}

/* Mobile Bottom Navigation Bar */
.mobile-nav-bar {
  display: none;
}

@media (max-width: 768px) {
  body {
    padding-bottom: 4.5rem;
  }

  .nav-tabs {
    display: none;
  }

  .nav-container {
    padding: 0.5rem 1rem;
  }

  .brand-title {
    font-size: 0.95rem;
  }

  .brand-subtitle {
    display: none;
  }

  .hero-card {
    grid-template-columns: 1fr;
    text-align: center;
    padding: 1.75rem 1rem;
    gap: 1.25rem;
  }

  .hero-cover {
    width: 130px;
    height: 170px;
    margin: 0 auto;
  }

  .hero-title {
    font-size: 1.4rem;
  }

  .hero-stats {
    justify-content: center;
    gap: 1.25rem;
  }

  .main-content {
    padding: 1rem 0.75rem;
  }

  .question-card {
    padding: 1.15rem;
    border-radius: 0.85rem;
  }

  .question-text {
    font-size: 1.05rem;
  }

  .option-btn {
    padding: 0.85rem 1rem;
    font-size: 0.9rem;
  }

  /* Bottom Bar */
  .mobile-nav-bar {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border-color);
    z-index: 100;
    justify-content: space-around;
    align-items: center;
    padding: 0.4rem 0.25rem;
    box-shadow: 0 -4px 12px rgba(0,0,0,0.1);
  }

  .mobile-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-muted);
    background: transparent;
    border: none;
    cursor: pointer;
    gap: 0.15rem;
    padding: 0.25rem;
    width: 20%;
  }

  .mobile-nav-item.active {
    color: var(--primary);
    font-weight: 700;
  }

  .mobile-nav-icon {
    font-size: 1.25rem;
  }
}

/* ==========================================================================
   ✨ 3D ICONS, SHIMMER GLOW & DENTIST MARKETING STYLES
   ========================================================================== */

/* 🌟 Shimmer Sweep & Glow Animations */
@keyframes shimmerGlow {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@keyframes shimmerSweep {
  0% { transform: translateX(-120%) rotate(25deg); }
  25% { transform: translateX(120%) rotate(25deg); }
  100% { transform: translateX(120%) rotate(25deg); }
}

@keyframes float3D {
  0%, 100% { transform: translateY(0px) rotate(0deg); }
  50% { transform: translateY(-7px) rotate(1deg); }
}

@keyframes pulseGlow3D {
  0%, 100% { box-shadow: 0 0 15px rgba(13, 148, 136, 0.4), inset 0 1px 1px rgba(255, 255, 255, 0.8); }
  50% { box-shadow: 0 0 30px rgba(245, 158, 11, 0.7), inset 0 2px 2px rgba(255, 255, 255, 0.9); }
}

/* Shimmer Text */
.shimmer-text {
  background: linear-gradient(90deg, #0d9488 0%, #38bdf8 25%, #f59e0b 50%, #38bdf8 75%, #0d9488 100%);
  background-size: 200% auto;
  color: transparent;
  -webkit-background-clip: text;
  background-clip: text;
  animation: shimmerGlow 3.5s linear infinite;
  display: inline-block;
}

.shimmer-gold {
  background: linear-gradient(90deg, #d97706 0%, #fbbf24 25%, #fff 50%, #fbbf24 75%, #d97706 100%);
  background-size: 200% auto;
  color: transparent;
  -webkit-background-clip: text;
  background-clip: text;
  animation: shimmerGlow 3s linear infinite;
}

/* Shimmer Button Effect */
.shimmer-btn {
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 20px -4px rgba(13, 148, 136, 0.5), inset 0 1px 1px rgba(255,255,255,0.6);
  transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.shimmer-btn::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.45) 50%, transparent 70%);
  transform: rotate(25deg);
  animation: shimmerSweep 3.5s infinite;
  pointer-events: none;
}

.shimmer-btn:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 12px 28px -4px rgba(13, 148, 136, 0.6), inset 0 2px 2px rgba(255,255,255,0.8);
}

/* 🧊 3D Icons & Containers */
.icon-3d-box {
  width: 56px;
  height: 56px;
  border-radius: 1rem;
  background: linear-gradient(135deg, #ffffff 0%, #f1f5f9 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  box-shadow: 
    0 10px 20px -5px rgba(13, 148, 136, 0.25),
    0 4px 6px -2px rgba(0, 0, 0, 0.05),
    inset 0 2px 0 rgba(255, 255, 255, 0.9),
    inset 0 -3px 0 rgba(0, 0, 0, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.8);
  transform: translateZ(10px);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  animation: float3D 4s ease-in-out infinite;
}

[data-theme="dark"] .icon-3d-box {
  background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
  border-color: rgba(255, 255, 255, 0.1);
  box-shadow: 
    0 10px 20px -5px rgba(0, 0, 0, 0.5),
    inset 0 1px 0 rgba(255, 255, 255, 0.15),
    inset 0 -3px 0 rgba(0, 0, 0, 0.4);
}

.badge-3d-gold {
  background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  color: #ffffff;
  padding: 0.35rem 0.85rem;
  border-radius: 2rem;
  font-weight: 700;
  font-size: 0.8rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.6);
  animation: pulseGlow3D 3s infinite;
}

/* 🩺 Marketing Dentist Section */
.marketing-dentist-section {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #115e59 100%);
  border-radius: 1.25rem;
  padding: 2rem;
  color: #ffffff;
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 40px -10px rgba(15, 23, 42, 0.4), inset 0 1px 1px rgba(255, 255, 255, 0.2);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.marketing-dentist-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 2rem;
  align-items: center;
}

@media (max-width: 900px) {
  .marketing-dentist-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
}

.dentist-hero-frame {
  position: relative;
  border-radius: 1rem;
  overflow: hidden;
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.5), 0 0 20px rgba(13, 148, 136, 0.4);
  border: 3px solid rgba(255, 255, 255, 0.2);
  transform: perspective(1000px) rotateY(-4deg);
  transition: transform 0.4s ease;
}

.dentist-hero-frame:hover {
  transform: perspective(1000px) rotateY(0deg) scale(1.02);
}

.dentist-hero-img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.dentist-features-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.dentist-feature-card {
  background: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 0.85rem;
  padding: 1rem;
  display: flex;
  align-items: center;
  gap: 0.85rem;
  transition: transform 0.3s ease, background 0.3s ease;
}

.dentist-feature-card:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-4px);
}

.dentist-badge-thumb {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  border: 2px solid #f59e0b;
  box-shadow: 0 0 15px rgba(245, 158, 11, 0.5);
  object-fit: cover;
}

/* ==========================================================================
   📖 REALISTIC FLIPBOOK / DIGITAL BOOK READER STYLES
   ========================================================================== */
.reader-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 1300px;
  margin: 0 auto;
  min-height: calc(100vh - 120px);
}

.reader-header-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 0.85rem 1.25rem;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  box-shadow: var(--card-shadow);
}

.reader-book-selector {
  display: flex;
  gap: 0.5rem;
  background: rgba(0, 0, 0, 0.04);
  padding: 0.3rem;
  border-radius: 0.65rem;
}

[data-theme="dark"] .reader-book-selector {
  background: rgba(255, 255, 255, 0.06);
}

.reader-part-btn {
  padding: 0.45rem 0.95rem;
  font-size: 0.85rem;
  font-weight: 700;
  border: none;
  background: transparent;
  color: var(--text-muted);
  border-radius: 0.5rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.reader-part-btn.active {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(13, 148, 136, 0.35);
}

.reader-controls-cluster {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.reader-select {
  padding: 0.45rem 0.85rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-main);
  color: var(--text-main);
  font-size: 0.85rem;
  font-weight: 600;
  max-width: 260px;
  cursor: pointer;
}

.reader-tool-btn {
  padding: 0.45rem 0.75rem;
  background: var(--bg-main);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.reader-tool-btn:hover {
  background: var(--primary-light);
  color: var(--primary-dark);
  border-color: var(--primary);
}

.reader-btn-group {
  display: flex;
  align-items: center;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  overflow: hidden;
  background: var(--bg-main);
}

.reader-btn-group .reader-tool-btn {
  border: none;
  border-radius: 0;
}

.reader-zoom-label {
  padding: 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  min-width: 45px;
  text-align: center;
}

/* --- Flipbook Stage & Physical Book Illusion --- */
.flipbook-stage-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  min-height: 600px;
  padding: 1rem 0;
}

.stage-nav-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(15, 23, 42, 0.65);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  cursor: pointer;
  z-index: 10;
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

.stage-nav-arrow:hover {
  background: var(--primary);
  transform: translateY(-50%) scale(1.1);
  box-shadow: 0 10px 25px rgba(13, 148, 136, 0.5);
}

.stage-nav-prev {
  left: 10px;
}

.stage-nav-next {
  right: 10px;
}

.flipbook-stage {
  position: relative;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  perspective: 1800px;
}

.open-book-frame {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: stretch;
  background: #2a2c33;
  padding: 12px;
  border-radius: 12px;
  box-shadow: 
    0 25px 60px -15px rgba(0, 0, 0, 0.6),
    0 10px 25px -5px rgba(0, 0, 0, 0.3),
    inset 0 1px 2px rgba(255, 255, 255, 0.2);
  transition: all 0.3s ease;
  max-width: 100%;
}

[data-theme="dark"] .open-book-frame {
  background: #11141c;
  box-shadow: 0 25px 70px rgba(0, 0, 0, 0.8), inset 0 1px 1px rgba(255, 255, 255, 0.1);
}

/* Physical Book Page Sheet */
.book-page-sheet {
  position: relative;
  background: #ffffff;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
  overflow: hidden;
  transition: transform 0.3s ease;
}

.book-page-sheet canvas {
  display: block;
  max-width: 100%;
  height: auto;
  background: #ffffff;
}

.left-page-sheet {
  border-radius: 6px 2px 2px 6px;
  box-shadow: 
    -5px 0 15px rgba(0, 0, 0, 0.1),
    inset -15px 0 25px -5px rgba(0, 0, 0, 0.15);
}

.right-page-sheet {
  border-radius: 2px 6px 6px 2px;
  box-shadow: 
    5px 0 15px rgba(0, 0, 0, 0.1),
    inset 15px 0 25px -5px rgba(0, 0, 0, 0.15);
}

.single-page-sheet {
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
}

/* Center Spine Shadow Illusion */
.book-spine-divider {
  width: 16px;
  background: linear-gradient(
    to right,
    rgba(0, 0, 0, 0.45) 0%,
    rgba(0, 0, 0, 0.15) 20%,
    rgba(255, 255, 255, 0.1) 50%,
    rgba(0, 0, 0, 0.15) 80%,
    rgba(0, 0, 0, 0.45) 100%
  );
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.5);
  z-index: 5;
  flex-shrink: 0;
}

.page-corner-fold {
  position: absolute;
  top: 0;
  width: 25px;
  height: 25px;
  pointer-events: none;
  z-index: 4;
}

.page-corner-left {
  left: 0;
  background: linear-gradient(135deg, rgba(0,0,0,0.08) 0%, transparent 60%);
}

.page-corner-right {
  right: 0;
  background: linear-gradient(-135deg, rgba(0,0,0,0.08) 0%, transparent 60%);
}

.page-sheet-footer {
  width: 100%;
  padding: 0.4rem 0.8rem;
  background: #fbfbfb;
  border-top: 1px solid #f0f0f0;
  font-size: 0.75rem;
  font-weight: 700;
  color: #64748b;
  text-align: center;
}

/* Loading Overlay inside Stage */
.reader-loading-overlay {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.75);
  backdrop-filter: blur(4px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  color: #ffffff;
  font-size: 0.95rem;
  font-weight: 700;
  z-index: 20;
  border-radius: 12px;
}

.reader-spinner {
  width: 44px;
  height: 44px;
  border: 4px solid rgba(255, 255, 255, 0.2);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Bottom Control Bar & Scrubber */
.reader-bottom-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 0.85rem 1.25rem;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
  box-shadow: var(--card-shadow);
}

.reader-page-counter {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.reader-page-box {
  width: 58px;
  text-align: center;
  padding: 0.35rem 0.4rem;
  border-radius: 0.4rem;
  border: 1px solid var(--border-color);
  background: var(--bg-main);
  color: var(--text-main);
  font-weight: 800;
  font-size: 0.9rem;
}

.reader-slider-wrap {
  flex: 1;
  min-width: 160px;
  max-width: 380px;
  display: flex;
  align-items: center;
}

.reader-range-slider {
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--border-color);
  accent-color: var(--primary);
  cursor: pointer;
}

/* Mobile Responsive Adjustments */
@media (max-width: 899px) {
  .stage-nav-arrow {
    width: 38px;
    height: 38px;
    font-size: 1rem;
  }
  .stage-nav-prev { left: 4px; }
  .stage-nav-next { right: 4px; }
  .open-book-frame {
    padding: 6px;
    border-radius: 8px;
  }
  .reader-controls-cluster {
    width: 100%;
    justify-content: space-between;
  }
  .reader-select {
    max-width: 100%;
    flex: 1;
  }
  .reader-slider-wrap {
    order: 5;
    width: 100%;
    max-width: 100%;
  }
}