#game-container {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

#cards-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.card {
    width: 100px;
    height: 100px;
    margin: 10px;
    perspective: 1000px;
    cursor: pointer;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

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

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 48px;
    font-weight: bold;
    border-radius: 5px;
}

.card-front {
    background-color: #ddd;
}

.card-back {
    background-color: #fff;
    transform: rotateY(180deg);
    border: 2px solid #ddd;
}

#message {
    margin-top: 20px;
    font-size: 24px;
}

#restart-button {
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 18px;
}