* {
  box-sizing: border-box;
}

body {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  padding: 20px;
}

.game-container {
  background: rgba(35, 39, 51, 0.95);
  backdrop-filter: blur(20px);
  border-radius: 20px;
  padding: 32px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
  min-width: 400px;
  max-width: 800px;
  text-align: center;
  transition: all 0.3s ease;
}

.game-title {
  font-size: 2.5rem;
  margin-bottom: 2rem;
  background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1);
  background-size: 200% 200%;
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: gradientShift 3s ease infinite;
}

@keyframes gradientShift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* Level Selection Styles */
.level-selection {
  animation: fadeIn 0.5s ease-in;
}

.level-selection h2 {
  font-size: 1.8rem;
  margin-bottom: 2rem;
  color: #e2e8f0;
}

.level-buttons {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 300px;
  margin: 0 auto;
}

.level-btn {
  background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  border: none;
  border-radius: 15px;
  padding: 1.5rem;
  color: white;
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-family: inherit;
  box-shadow: 0 8px 25px rgba(79, 172, 254, 0.3);
}

.level-btn:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 35px rgba(79, 172, 254, 0.4);
}

.level-btn.medium {
  background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
  box-shadow: 0 8px 25px rgba(250, 112, 154, 0.3);
}

.level-btn.medium:hover {
  box-shadow: 0 15px 35px rgba(250, 112, 154, 0.4);
}

.level-btn.hard {
  background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
  box-shadow: 0 8px 25px rgba(255, 107, 107, 0.3);
}

.level-btn.hard:hover {
  box-shadow: 0 15px 35px rgba(255, 107, 107, 0.4);
}

.level-icon {
  font-size: 2rem;
}

.level-name {
  font-size: 1.3rem;
  font-weight: bold;
}

.level-desc {
  font-size: 0.9rem;
  opacity: 0.9;
}

/* Game Screen Styles */
.game-screen {
  animation: slideIn 0.5s ease-out;
}

.game-header {
  margin-bottom: 1.5rem;
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 1rem;
}

.current-level {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-weight: bold;
}

.board {
  display: grid;
  gap: 8px;
  margin: 24px auto;
  justify-content: center;
  max-width: 100%;
  transition: all 0.3s ease;
}

/* Dynamic grid sizing */
.board.easy {
  grid-template-columns: repeat(4, 60px);
  max-width: 280px;
}

.board.medium {
  grid-template-columns: repeat(8, 50px);
  max-width: 440px;
}

.board.hard {
  grid-template-columns: repeat(8, 45px);
  max-width: 400px;
}

.card {
  aspect-ratio: 1;
  background: linear-gradient(145deg, #3a4158, #2d3748);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  user-select: none;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.1) 50%, transparent 70%);
  transform: translateX(-100%);
  transition: transform 0.6s;
}

.card:hover::before {
  transform: translateX(100%);
}

.card:hover {
  transform: translateY(-3px) scale(1.05);
  box-shadow: 0 8px 25px rgba(0,0,0,0.3);
}

.card.flipped {
  background: linear-gradient(145deg, #4ecdc4, #44a08d);
  transform: rotateY(180deg) scale(1.05);
  cursor: default;
  animation: cardFlip 0.6s ease-in-out;
}

.card.matched {
  background: linear-gradient(145deg, #56ab2f, #a8e6cf);
  color: #fff;
  animation: matchPulse 0.8s ease-in-out;
  transform: scale(1.1);
}

.card.wrong {
  animation: wrongShake 0.5s ease-in-out;
}

@keyframes cardFlip {
  0% { transform: rotateY(0deg); }
  50% { transform: rotateY(90deg) scale(1.1); }
  100% { transform: rotateY(180deg) scale(1.05); }
}

@keyframes matchPulse {
  0%, 100% { transform: scale(1.05); }
  50% { transform: scale(1.2); box-shadow: 0 0 20px rgba(86, 171, 47, 0.6); }
}

@keyframes wrongShake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

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

@keyframes slideIn {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

.actions {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2rem;
}

.back-btn, .reset-btn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  border: none;
  border-radius: 12px;
  padding: 12px 24px;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: inherit;
  font-weight: 500;
}

.back-btn:hover, .reset-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

/* Modal Styles */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
  animation: modalFadeIn 0.3s ease;
}

.modal-content {
  background: linear-gradient(145deg, #232733, #2d3748);
  border-radius: 20px;
  padding: 2rem;
  text-align: center;
  max-width: 400px;
  width: 90%;
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
  animation: modalSlideIn 0.3s ease;
}

.modal-content h2 {
  margin-bottom: 1rem;
  color: #4ecdc4;
}

.success-stats {
  display: flex;
  justify-content: space-around;
  margin: 1.5rem 0;
  padding: 1rem;
  background: rgba(0,0,0,0.2);
  border-radius: 10px;
}

.modal-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-top: 1.5rem;
}

.play-again-btn, .change-level-btn {
  background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  color: white;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: inherit;
}

.change-level-btn {
  background: linear-gradient(135deg, #fa709a 0%, #fee140 100%);
}

.play-again-btn:hover, .change-level-btn:hover {
  transform: translateY(-2px);
}

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

@keyframes modalSlideIn {
  from { transform: translateY(-50px) scale(0.9); }
  to { transform: translateY(0) scale(1); }
}

.hidden {
  display: none !important;
}

/* Responsive Design */
@media (max-width: 480px) {
  /* Small phones */
  body {
    padding: 10px;
    min-height: 100vh;
    display: flex;
    align-items: flex-start;
    padding-top: 20px;
  }
  
  .game-container {
    padding: 16px;
    margin: 0;
    min-width: unset;
    width: 100%;
    max-width: 100vw;
    border-radius: 12px;
  }
  
  .game-title {
    font-size: 1.8rem;
    margin-bottom: 1rem;
  }
  
  .level-buttons {
    max-width: 100%;
  }
  
  .level-btn {
    padding: 1rem;
    font-size: 0.9rem;
  }
  
  .level-icon {
    font-size: 1.5rem;
  }
  
  .level-name {
    font-size: 1.1rem;
  }
  
  .level-desc {
    font-size: 0.8rem;
  }
  
  .board.easy {
    grid-template-columns: repeat(4, 65px);
    gap: 8px;
    max-width: 100%;
  }
  
  .board.medium {
    grid-template-columns: repeat(8, 35px);
    gap: 6px;
    max-width: 100%;
  }
  
  .board.hard {
    grid-template-columns: repeat(8, 32px);
    gap: 4px;
    max-width: 100%;
  }
  
  .card {
    font-size: 1.2rem;
    border-radius: 8px;
  }
  
  .stats {
    grid-template-columns: 1fr;
    gap: 0.5rem;
    font-size: 0.85rem;
    text-align: center;
  }
  
  .current-level {
    padding: 0.4rem 0.8rem;
    font-size: 0.8rem;
  }
  
  .actions {
    flex-direction: column;
    gap: 0.8rem;
  }
  
  .back-btn, .reset-btn {
    padding: 10px 16px;
    font-size: 0.9rem;
    width: 100%;
  }
  
  .modal-content {
    padding: 1.5rem;
    margin: 20px;
    width: calc(100% - 40px);
  }
  
  .modal-actions {
    flex-direction: column;
    gap: 0.8rem;
  }
  
  .play-again-btn, .change-level-btn {
    width: 100%;
    padding: 12px;
  }
}

@media (max-width: 768px) and (min-width: 481px) {
  /* Medium phones and small tablets */
  .game-container {
    padding: 20px;
    margin: 15px;
    max-width: 90vw;
  }
  
  .game-title {
    font-size: 2.2rem;
  }
  
  .board.easy {
    grid-template-columns: repeat(4, 70px);
    gap: 10px;
  }
  
  .board.medium {
    grid-template-columns: repeat(8, 42px);
    gap: 8px;
  }
  
  .board.hard {
    grid-template-columns: repeat(8, 38px);
    gap: 6px;
  }
  
  .card {
    font-size: 1.6rem;
  }
  
  .stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 0.8rem;
    font-size: 0.95rem;
  }
}

@media (max-width: 1024px) and (min-width: 769px) {
  /* Tablets */
  .game-container {
    padding: 28px;
    margin: 20px;
  }
  
  .board.easy {
    grid-template-columns: repeat(4, 80px);
  }
  
  .board.medium {
    grid-template-columns: repeat(8, 50px);
  }
  
  .board.hard {
    grid-template-columns: repeat(8, 45px);
  }
}

@media (orientation: landscape) and (max-height: 600px) {
  /* Landscape mobile phones */
  body {
    padding: 5px;
    align-items: center;
  }
  
  .game-container {
    padding: 12px;
    margin: 5px;
  }
  
  .game-title {
    font-size: 1.5rem;
    margin-bottom: 0.8rem;
  }
  
  .level-buttons {
    flex-direction: row;
    justify-content: space-around;
  }
  
  .level-btn {
    padding: 0.8rem;
    min-width: 120px;
  }
  
  .stats {
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    font-size: 0.8rem;
  }
  
  .board.easy {
    grid-template-columns: repeat(4, 50px);
    gap: 6px;
  }
  
  .board.medium {
    grid-template-columns: repeat(8, 30px);
    gap: 4px;
  }
  
  .board.hard {
    grid-template-columns: repeat(8, 28px);
    gap: 3px;
  }
  
  .card {
    font-size: 1rem;
  }
  
  .actions {
    flex-direction: row;
    gap: 1rem;
  }
}

/* Touch improvements for mobile */
@media (hover: none) and (pointer: coarse) {
  .card:hover {
    transform: none;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
  }
  
  .card:active {
    transform: scale(0.95);
  }
  
  .level-btn:hover {
    transform: none;
  }
  
  .level-btn:active {
    transform: scale(0.98);
  }
  
  .back-btn:hover, .reset-btn:hover {
    transform: none;
  }
  
  .back-btn:active, .reset-btn:active {
    transform: scale(0.98);
  }
}