/* 
  Alphabet Odyssey - Scrollytelling Stylesheet
  Vibrant Glassmorphic Aesthetics, Responsive Typography & Smooth Transitions
*/

:root {
  --font-heading: 'Fredoka', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-body: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  --bg-dark: #0a0518;
  --bg-card: rgba(18, 14, 34, 0.78);
  --bg-card-border: rgba(255, 255, 255, 0.12);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --accent-glow: rgba(255, 71, 87, 0.35);
  
  --radius-card: 24px;
  --radius-pill: 9999px;
  
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-smooth: cubic-bezier(0.16, 1, 0.3, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

html {
  scroll-behavior: smooth;
  color-scheme: dark;
  background-color: var(--bg-dark);
}

body {
  font-family: var(--font-body);
  color: var(--text-main);
  background-color: var(--bg-dark);
  overflow-x: hidden;
  line-height: 1.6;
}

/* 3D WebGL Background Container */
#webgl-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 1;
  pointer-events: auto;
  cursor: grab;
  transition: opacity 0.5s ease;
}

#webgl-container:active {
  cursor: grabbing;
}

/* Background Atmospheric Gradient Mesh */
.cosmic-backdrop {
  position: fixed;
  inset: 0;
  z-index: 0;
  background: radial-gradient(circle at 50% 30%, #1a0f35 0%, #0d061c 60%, #06020c 100%);
  opacity: 0.9;
  pointer-events: none;
  transition: background 0.8s ease;
}

/* Top Navigation Bar */
.top-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  z-index: 50;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(10, 5, 24, 0.65);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.back-portfolio-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.45rem 0.9rem;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-pill);
  transition: all 0.25s ease;
}

.back-portfolio-link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.14);
  transform: translateX(-2px);
}

.logo-badge {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: #fff;
}

.logo-icon {
  font-size: 1.35rem;
  animation: floatOrb 3s ease-in-out infinite;
}

/* Header Controls */
.header-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.lang-switch-group {
  display: flex;
  align-items: center;
  gap: 3px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-pill);
  padding: 3px;
}

.lang-btn {
  display: inline-flex;
  align-items: center;
  padding: 0.32rem 0.75rem;
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: var(--radius-pill);
  transition: all 0.2s ease;
}

.lang-btn:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
}

.lang-btn.active {
  color: #fff;
  background: linear-gradient(135deg, #ff4757, #ff6b81);
  box-shadow: 0 0 10px rgba(255, 71, 87, 0.4);
}

.ctrl-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: var(--text-main);
  padding: 0.45rem 1rem;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: var(--radius-pill);
  cursor: pointer;
  backdrop-filter: blur(8px);
  transition: all 0.2s ease;
}

.ctrl-btn:hover {
  background: rgba(255, 255, 255, 0.18);
  transform: translateY(-1px);
}

.ctrl-btn:active {
  transform: translateY(1px);
}

.ctrl-btn.active {
  background: linear-gradient(135deg, #ff4757, #ff6b81);
  border-color: #ff4757;
  color: #fff;
  box-shadow: 0 0 16px rgba(255, 71, 87, 0.4);
}

/* Global Progress Line Bar */
.scroll-progress-bar {
  position: fixed;
  top: 67px;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, #ff4757, #ffa502, #2ed573, #1e90ff, #9c88ff);
  z-index: 51;
  transition: width 0.1s linear;
}

/* Scrollytelling Scroll Track Container */
.story-scroll-container {
  position: relative;
  z-index: 10;
  width: 100%;
  pointer-events: none; /* Let clicks pass to 3D canvas except on cards */
}

/* General Chapter Section Structure */
.story-chapter {
  position: relative;
  min-height: 125vh;
  display: flex;
  align-items: center;
  padding: 2rem 5%;
}

/* Hero / Prologue Chapter */
.hero-chapter {
  min-height: 100vh;
  justify-content: center;
  text-align: center;
  padding-top: 5rem;
}

.hero-glass-card {
  pointer-events: auto;
  max-width: 680px;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: var(--radius-card);
  padding: 3rem 2.5rem;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.6);
  animation: fadeInDown 1s var(--ease-smooth);
}

.hero-pill {
  display: inline-block;
  padding: 0.35rem 1rem;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.1);
  font-size: 0.85rem;
  font-weight: 600;
  color: #fed330;
  margin-bottom: 1.25rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 1.25rem;
  background: linear-gradient(135deg, #ffffff 30%, #ffd32a 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1.15rem;
  color: #cbd5e1;
  margin-bottom: 2rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.primary-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.8rem;
  border-radius: var(--radius-pill);
  background: linear-gradient(135deg, #ff4757, #ff6b81);
  color: #fff;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 0 10px 25px rgba(255, 71, 87, 0.4);
  transition: all 0.3s var(--ease-spring);
}

.primary-cta:hover {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 14px 30px rgba(255, 71, 87, 0.55);
}

.secondary-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.6rem;
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.secondary-cta:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Letter Chapter Alternating Layout */
.story-chapter:nth-child(even) {
  justify-content: flex-start;
  padding-left: 6%;
}

.story-chapter:nth-child(odd) {
  justify-content: flex-end;
  padding-right: 6%;
}

/* Letter Glassmorphic Card */
.letter-card {
  pointer-events: auto;
  width: 100%;
  max-width: 480px;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: var(--radius-card);
  padding: 2.25rem;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.55);
  position: relative;
  overflow: hidden;
  transform: translateY(30px);
  opacity: 0.25;
  transition: transform 0.6s var(--ease-smooth), opacity 0.6s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}

.story-chapter.active .letter-card {
  transform: translateY(0);
  opacity: 1;
  border-color: rgba(255, 255, 255, 0.28);
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.7), 0 0 40px var(--card-glow, rgba(255, 71, 87, 0.2));
}

/* Top Card Header with Letter Stamp & Phonics */
.card-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.stamp-box {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.letter-stamp {
  width: 60px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--card-accent, #ff4757), #ffa502);
  color: #fff;
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 800;
  border-radius: 16px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
  cursor: pointer;
  transition: transform 0.3s var(--ease-spring);
}

.letter-stamp:hover {
  transform: scale(1.1) rotate(-4deg);
}

.phonics-badge {
  display: inline-block;
  padding: 0.3rem 0.8rem;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 600;
  color: #cbd5e1;
}

.voice-pronounce-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.16);
  color: #fff;
  font-size: 1.15rem;
  cursor: pointer;
  transition: all 0.25s var(--ease-spring);
}

.voice-pronounce-btn:hover {
  background: var(--card-accent, #ff4757);
  transform: scale(1.12);
  box-shadow: 0 0 18px var(--card-glow, rgba(255, 71, 87, 0.45));
}

.voice-pronounce-btn:active {
  transform: scale(0.92);
}

/* Card Body Content */
.letter-title {
  font-family: var(--font-heading);
  font-size: 1.65rem;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 0.9rem;
  color: #fff;
}

.rhyme-box {
  background: rgba(255, 255, 255, 0.05);
  border-left: 4px solid var(--card-accent, #ff4757);
  padding: 0.85rem 1.1rem;
  border-radius: 4px 12px 12px 4px;
  margin-bottom: 1.15rem;
  font-style: italic;
  font-size: 0.98rem;
  color: #f1f5f9;
  line-height: 1.55;
}

.story-text {
  font-size: 0.95rem;
  color: #cbd5e1;
  margin-bottom: 1.4rem;
  line-height: 1.65;
}

/* Vocabulary Tags Cloud */
.vocab-section-title {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  font-weight: 700;
  margin-bottom: 0.6rem;
}

.vocab-tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
}

.vocab-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.85rem;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 500;
  color: #e2e8f0;
  cursor: pointer;
  transition: all 0.2s ease;
}

.vocab-chip:hover {
  background: rgba(255, 255, 255, 0.18);
  border-color: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
  color: #fff;
}

.card-hint-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: #64748b;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 0.85rem;
}

/* Epilogue / Master Chapter */
.epilogue-chapter {
  min-height: 100vh;
  justify-content: center;
  text-align: center;
}

.epilogue-card {
  pointer-events: auto;
  max-width: 600px;
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: var(--radius-card);
  padding: 3rem 2.5rem;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.6);
}

.trophy-badge {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  animation: bounceTrophy 2s ease infinite;
}

/* Floating Alphabet Timeline / Scrubber Rail (Right Edge) */
.alphabet-scrubber-rail {
  position: fixed;
  right: 1.5rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: 3px;
  background: rgba(10, 5, 24, 0.65);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 0.5rem 0.35rem;
  border-radius: var(--radius-pill);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.scrub-item {
  width: 26px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: 0.75rem;
  font-weight: 700;
  color: #64748b;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.scrub-item:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.15);
  transform: scale(1.2);
}

.scrub-item.active {
  color: #fff;
  background: #ff4757;
  box-shadow: 0 0 10px rgba(255, 71, 87, 0.6);
  transform: scale(1.15);
}

/* Floating Bottom HUD / Quick Nav on Mobile */
.mobile-scrub-bar {
  display: none;
  position: fixed;
  bottom: 1.25rem;
  left: 50%;
  transform: translateX(-50%);
  width: 90%;
  max-width: 440px;
  background: rgba(18, 14, 34, 0.88);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-pill);
  padding: 0.5rem 1rem;
  z-index: 45;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.6);
}

.mobile-letter-indicator {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
}

.mobile-nav-btn {
  background: rgba(255, 255, 255, 0.12);
  border: none;
  color: #fff;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Toast Message */
.story-toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  padding: 0.75rem 1.6rem;
  border-radius: var(--radius-pill);
  font-size: 0.92rem;
  font-weight: 600;
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.6);
  z-index: 100;
  opacity: 0;
  transition: all 0.4s var(--ease-spring);
  pointer-events: none;
}

.story-toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* Animations */
@keyframes floatOrb {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

@keyframes bounceTrophy {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15) rotate(6deg); }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Media Queries */
@media (max-width: 900px) {
  .alphabet-scrubber-rail {
    display: none;
  }
  
  .mobile-scrub-bar {
    display: flex;
  }

  .story-chapter {
    min-height: 110vh;
    justify-content: center !important;
    padding: 1.5rem 1.25rem !important;
  }

  .letter-card {
    max-width: 100%;
    padding: 1.75rem;
  }

  .top-header {
    padding: 0 1.25rem;
  }

  .hero-glass-card {
    padding: 2rem 1.5rem;
  }
}