body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 0;
    padding: 0;
}

#levelSelection, #gameArea {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

.card {
    display: inline-block;
    width: 150px;
    height: 200px;
    margin: 10px;
    perspective: 1000px;
    position: relative;
}

.card-inner {
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
    cursor: pointer;
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border: 2px solid #333;
    border-radius: 10px;
}

.card-front {
    background-color: #f0f0f0;
    z-index: 2;
}

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

.card-back img {
    max-width: 100px;
    max-height: 150px;
}

.paired-cards {
    transform: scale(1.2);
    z-index: 10;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 20px;
    width: 70%;
    max-width: 500px;
    border-radius: 10px;
}

#result img {
    max-width: 200px;
}