* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Poppins', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #ffffff;
}

.game-container {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: 1px solid rgba(255, 255, 255, 0.18);
}

h1 {
    margin-bottom: 20px;
    font-weight: 600;
    text-align: center;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.game-board {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    margin-bottom: 20px;
}

.card {
    width: 100px;
    height: 100px;
    background-color: #3498db;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 40px;
    cursor: pointer;
    transition: transform 0.6s;
    transform-style: preserve-3d;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.card:hover {
    transform: scale(1.05);
}

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

.card .front, .card .back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 10px;
}

.card .front {
    background-color: #3498db;
}

.card .back {
    background-color: #2ecc71;
    transform: rotateY(180deg);
}

.game-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
}

#reset-button {
    padding: 10px 20px;
    font-size: 16px;
    background-color: #e74c3c;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.1s ease;
}

#reset-button:hover {
    background-color: #c0392b;
    transform: translateY(-2px);
}

#reset-button:active {
    transform: translateY(0);
}

@keyframes pulse {
    0% {
        transform: scale(1);
    }
    
    50% {
        transform: scale(1.05);
    }
    
    100% {
        transform: scale(1);
    }
}

.matched {
    animation: pulse 0.5s ease-in-out;
}

@media (max-width: 480px) {
    .game-board {
        grid-template-columns: repeat(3, 1fr);
    }

    .card {
        width: 80px;
        height: 80px;
        font-size: 30px;
    }

    .game-info {
        flex-direction: column;
        align-items: stretch;
    }

    #reset-button {
        margin-top: 10px;
    }
}