/* Reset and base styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Noto Sans", -apple-system, BlinkMacSystemFont, "Segoe UI",
    Helvetica, Arial, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  color: #333;
  line-height: 1.6;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 40px;
  color: white;
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 20px;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.progress-container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
}

.progress-bar {
  width: 200px;
  height: 8px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: #4caf50;
  border-radius: 4px;
  transition: width 0.3s ease;
  width: 4.17%; /* 1/24 * 100% */
}

.progress-text {
  font-size: 1.1rem;
  font-weight: 600;
  color: white;
}

/* Main content */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 30px;
}

/* Flashcard */
.flashcard-container {
  perspective: 1000px;
  width: 100%;
  max-width: 400px;
  height: 300px;
}

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

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 30px;
  text-align: center;
}

.flashcard-front {
  background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
  border: 2px solid #e9ecef;
}

.flashcard-back {
  background: linear-gradient(135deg, #4caf50 0%, #45a049 100%);
  color: white;
  transform: rotateY(180deg);
}

/* Letter display */
.letter-display {
  margin-bottom: 20px;
}

.letter-uppercase {
  font-family: "Noto Sans Greek", "Noto Sans", serif;
  font-size: 4rem;
  font-weight: 700;
  color: #2c3e50;
  margin-bottom: 10px;
  line-height: 1;
}

.letter-lowercase {
  font-family: "Noto Sans Greek", "Noto Sans", serif;
  font-size: 3rem;
  font-weight: 600;
  color: #34495e;
  line-height: 1;
}

/* Transliteration display */
.transliteration-display {
  text-align: center;
}

.transliteration {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 15px;
  color: white;
}

.pronunciation {
  font-size: 1.5rem;
  font-weight: 400;
  margin-bottom: 10px;
  color: rgba(255, 255, 255, 0.9);
  font-style: italic;
}

.romanization {
  font-size: 1.2rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.8);
}

/* Card hints */
.card-hint {
  font-size: 0.9rem;
  color: #6c757d;
  margin-top: auto;
  opacity: 0.7;
}

.flashcard-back .card-hint {
  color: rgba(255, 255, 255, 0.7);
}

/* Controls */
.controls {
  display: flex;
  gap: 20px;
  align-items: center;
}

.control-btn {
  width: 60px;
  height: 60px;
  border: none;
  border-radius: 50%;
  background: white;
  color: #667eea;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  font-size: 1.2rem;
}

.control-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
  background: #f8f9fa;
}

.control-btn:active {
  transform: translateY(0);
}

.control-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.flip-btn {
  background: #4caf50;
  color: white;
  width: 70px;
  height: 70px;
}

.flip-btn:hover {
  background: #45a049;
}

/* Action buttons */
.action-buttons {
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
  justify-content: center;
}

.action-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border: none;
  border-radius: 25px;
  background: rgba(255, 255, 255, 0.2);
  color: white;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.action-btn:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: translateY(-1px);
}

/* Pronunciation Section */
.pronunciation-section {
  margin: 40px 0;
  padding: 30px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 16px;
  backdrop-filter: blur(10px);
  color: white;
  text-align: center;
}

.pronunciation-section h3 {
  font-size: 1.5rem;
  margin-bottom: 10px;
  color: white;
  font-weight: 600;
}

.pronunciation-hint {
  font-size: 1rem;
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 25px;
  font-style: italic;
}

.alphabet-table {
  display: flex;
  justify-content: center;
}

.alphabet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
  gap: 12px;
  max-width: 800px;
  width: 100%;
}

.letter-item {
  background: rgba(255, 255, 255, 0.15);
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: 12px;
  padding: 15px 10px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.letter-item:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.4);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
}

.letter-item:active {
  transform: translateY(0) scale(0.98);
}

.letter-item.speaking {
  background: rgba(76, 175, 80, 0.3);
  border-color: #4caf50;
  animation: pulse 1s ease-in-out infinite;
}

.letter-item-upper {
  font-family: "Noto Sans Greek", "Noto Sans", serif;
  font-size: 1.8rem;
  font-weight: 700;
  color: white;
  line-height: 1;
  margin-bottom: 4px;
}

.letter-item-lower {
  font-family: "Noto Sans Greek", "Noto Sans", serif;
  font-size: 1.4rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.9);
  line-height: 1;
  margin-bottom: 6px;
}

.letter-item-name {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

@keyframes pulse {
  0%,
  100% {
    box-shadow: 0 0 0 0 rgba(76, 175, 80, 0.4);
  }
  50% {
    box-shadow: 0 0 0 10px rgba(76, 175, 80, 0);
  }
}

/* Footer */
.footer {
  margin-top: 40px;
  text-align: center;
  color: white;
}

.instructions h3 {
  font-size: 1.2rem;
  margin-bottom: 10px;
  color: rgba(255, 255, 255, 0.9);
}

.instructions ul {
  list-style: none;
  display: inline-block;
  text-align: left;
}

.instructions li {
  margin-bottom: 5px;
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.9rem;
}

/* Responsive design */
@media (max-width: 768px) {
  .container {
    padding: 15px;
  }

  .header h1 {
    font-size: 2rem;
  }

  .flashcard-container {
    max-width: 350px;
    height: 280px;
  }

  .letter-uppercase {
    font-size: 3.5rem;
  }

  .letter-lowercase {
    font-size: 2.5rem;
  }

  .transliteration {
    font-size: 2rem;
  }

  .controls {
    gap: 15px;
  }

  .control-btn {
    width: 50px;
    height: 50px;
  }

  .flip-btn {
    width: 60px;
    height: 60px;
  }

  .progress-container {
    flex-direction: column;
    gap: 10px;
  }

  .progress-bar {
    width: 150px;
  }
}

@media (max-width: 480px) {
  .header h1 {
    font-size: 1.8rem;
  }

  .flashcard-container {
    max-width: 300px;
    height: 250px;
  }

  .letter-uppercase {
    font-size: 3rem;
  }

  .letter-lowercase {
    font-size: 2rem;
  }

  .transliteration {
    font-size: 1.8rem;
  }

  .action-buttons {
    flex-direction: column;
    align-items: center;
  }

  .instructions ul {
    text-align: center;
  }

  .alphabet-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
  }

  .letter-item {
    padding: 10px 8px;
  }

  .letter-item-upper {
    font-size: 1.4rem;
  }

  .letter-item-lower {
    font-size: 1.1rem;
  }

  .letter-item-name {
    font-size: 0.7rem;
  }
}

/* Animation for card transitions */
@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.flashcard-container {
  animation: slideIn 0.3s ease-out;
}

/* Focus styles for accessibility */
.control-btn:focus,
.action-btn:focus,
.flashcard:focus,
.letter-item:focus {
  outline: 2px solid #4caf50;
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  .flashcard-front {
    background: white;
    border: 3px solid black;
    color: black;
  }

  .flashcard-back {
    background: black;
    border: 3px solid white;
    color: white;
  }

  .control-btn,
  .action-btn {
    border: 2px solid currentColor;
  }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .flashcard {
    transition: none;
  }

  .letter-item.speaking {
    animation: none;
    background: rgba(76, 175, 80, 0.3);
  }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  body {
    background: linear-gradient(135deg, #2c3e50 0%, #4a6741 100%);
  }

  .flashcard-front {
    background: linear-gradient(135deg, #34495e 0%, #2c3e50 100%);
    border-color: #5a6c7d;
    color: white;
  }

  .letter-uppercase,
  .letter-lowercase {
    color: white;
  }

  .card-hint {
    color: #bdc3c7;
  }
}

/* Print styles */
@media print {
  body {
    background: white;
    color: black;
  }

  .controls,
  .action-buttons,
  .pronunciation-section {
    display: none;
  }

  .flashcard {
    background: white;
    border: 2px solid black;
    box-shadow: none;
  }

  .flashcard-back {
    display: block;
    transform: none;
  }
}