/* CSS Variables */
:root {
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --card-bg: rgba(255, 255, 255, 0.05);
  --border-color: rgba(255, 255, 255, 0.1);
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.8);
  --border-radius: 16px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-light: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 8px 25px rgba(0, 0, 0, 0.2);
  --shadow-heavy: 0 20px 40px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Poppins', sans-serif;
    background: #0A0A23;
    color: #FFFFFF;
    margin: 0;
    min-height: 100vh;
    user-select: none;
    touch-action: manipulation;
}

/* Difficulty Selection Screen */
.difficulty-selection {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 70px);
    padding: 20px;
}

.difficulty-container {
    text-align: center;
    max-width: 800px;
    width: 100%;
}

.difficulty-container h2 {
    font-size: 2.5rem;
    margin-bottom: 40px;
    color: #FFFFFF;
}

.difficulty-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.difficulty-btn {
    background: linear-gradient(135deg, #003566, #001D3D);
    border: 2px solid #00B4DB;
    border-radius: 15px;
    padding: 30px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    color: #FFFFFF;
    text-align: center;
}

.difficulty-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 180, 219, 0.3);
    border-color: #4CAF50;
}

.difficulty-icon {
    font-size: 4rem;
    margin-bottom: 15px;
}

.difficulty-btn h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: #00B4DB;
}

.difficulty-btn p {
    font-size: 1rem;
    opacity: 0.8;
    line-height: 1.4;
}

/* Game Main */
.game-main {
    padding: 20px;
    max-width: 1200px;
    margin: 0 auto;
}

/* Game Info */
.game-info {
    margin-bottom: 20px;
}

.stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
}

.stat {
    text-align: center;
    background: linear-gradient(135deg, #003566, #001D3D);
    border: 2px solid #00B4DB;
    border-radius: 10px;
    padding: 15px 25px;
    min-width: 120px;
}

.stat-label {
    display: block;
    font-size: 0.9rem;
    opacity: 0.8;
    margin-bottom: 5px;
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: bold;
    color: #00B4DB;
}

/* Game Board */
.game-board {
    display: grid;
    gap: 10px;
    justify-content: center;
    margin: 0 auto;
    max-width: 600px;
}

.game-board.easy {
    grid-template-columns: repeat(4, 1fr);
}

.game-board.medium {
    grid-template-columns: repeat(6, 1fr);
}

.game-board.hard {
    grid-template-columns: repeat(8, 1fr);
}

/* Memory Cards */
.memory-card {
    aspect-ratio: 1;
    background: linear-gradient(135deg, #003566, #001D3D);
    border: 2px solid #00B4DB;
    border-radius: 10px;
    cursor: pointer;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    min-height: 80px;
}

.memory-card:hover {
    border-color: #4CAF50;
}

.memory-card.flipped {
    transform: rotateY(180deg);
}

.memory-card.matched {
    border-color: #4CAF50;
    background: linear-gradient(135deg, #4CAF50, #45a049);
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    font-size: 2rem;
}

.card-back {
    background: linear-gradient(135deg, #003566, #001D3D);
    color: #00B4DB;
}

.card-front {
    background: linear-gradient(135deg, #FFFFFF, #F0F8FF);
    color: #0A0A23;
    transform: rotateY(180deg);
    font-size: 2.5rem;
}

/* Win Modal and Pause Modal */
.win-modal, .pause-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 10, 35, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.win-content {
    background: linear-gradient(135deg, #003566, #001D3D);
    border: 2px solid #00B4DB;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    max-width: 400px;
    width: 90%;
}

.win-content h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: #4CAF50;
}

.win-stats {
    margin: 20px 0;
}

.win-stats p {
    font-size: 1.2rem;
    margin: 10px 0;
    color: #00B4DB;
}

.win-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 20px;
}

.win-buttons button {
    background: linear-gradient(45deg, #4CAF50, #45a049);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

.win-buttons button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

/* Animations */
@keyframes cardFlip {
    0% { transform: rotateY(0deg); }
    100% { transform: rotateY(180deg); }
}

@keyframes matchPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.memory-card.matched {
    animation: matchPulse 0.5s ease-in-out;
}

/* Responsive design */
@media (max-width: 768px) {
    .stats {
        gap: 20px;
    }
    
    .stat {
        padding: 10px 15px;
        min-width: 100px;
    }
    
    .stat-value {
        font-size: 1.2rem;
    }
    
    .game-board {
        gap: 6px;
        max-width: 350px;
    }
    
    .game-board.medium {
        max-width: 300px;
    }
    
    .game-board.hard {
        max-width: 280px;
    }
    
    .memory-card {
        min-height: 50px;
    }
    
    .card-face {
        font-size: 1.2rem;
    }
    
    .card-front {
        font-size: 1.5rem;
    }
    
    .difficulty-container h2 {
        font-size: 2rem;
    }
    
    .difficulty-buttons {
        grid-template-columns: 1fr;
        gap: 20px;
    }
}

@media (max-width: 480px) {
    .game-board {
        gap: 4px;
        max-width: 280px;
    }
    
    .game-board.medium {
        max-width: 240px;
    }
    
    .game-board.hard {
        max-width: 200px;
    }
    
    .memory-card {
        min-height: 35px;
    }
    
    .card-face {
        font-size: 1rem;
    }
    
    .card-front {
        font-size: 1.2rem;
    }
    
    .stats {
        gap: 15px;
    }
    
    .stat {
        padding: 8px 12px;
        min-width: 80px;
    }
    
    .stat-label {
        font-size: 0.8rem;
    }
    
    .stat-value {
        font-size: 1rem;
    }
}/* Mobile o
ptimizations */
@media (max-width: 768px) {
  .memory-card {
    min-height: 60px !important;
    min-width: 60px !important;
    touch-action: manipulation;
  }
  
  .game-board.easy {
    gap: 8px !important;
  }
  
  .game-board.medium {
    gap: 6px !important;
  }
  
  .game-board.hard {
    gap: 4px !important;
  }
  
  .difficulty-btn {
    padding: 15px 20px !important;
    touch-action: manipulation;
  }
}

/* Touch feedback */
.memory-card:active {
  transform: scale(0.95);
  transition: transform 0.1s ease;
}

.difficulty-btn:active {
  transform: scale(0.95);
  transition: transform 0.1s ease;
}