body {
    font-family: 'Arial', sans-serif;
    background-color: #0a0a0a; /* Dark Background */
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    color: #33ff33; /* Neon Green Text */
}

.game-container {
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.grid {
    display: grid;
    grid-template-columns: repeat(4, 100px);
    grid-gap: 10px;
    margin: 0 auto;
}

.card {
    width: 100px;
    height: 100px;
    position: relative;
    perspective: 1000px;
    cursor: pointer;
    border: 1px solid #33ff33; /* Neon Green Border */
}

.card .front,
.card .back {
    width: 100%;
    height: 100%;
    position: absolute;
    backface-visibility: hidden;
    border-radius: 5px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2em;
    font-weight: bold;
}

.card .front {
    background-color: #121212; /* Dark Front */
    color: #33ff33; /* Neon Green Text */
}

.card .back {
    background-color: #333; /* Dark Back */
    color: #fff;
    transform: rotateY(180deg);
}

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

.card.flipped .back {
    transform: rotateY(360deg);
}

.button {
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 1em;
    border: 2px solid #33ff33; /* Neon Green Border */
    border-radius: 5px;
    background-color: transparent;
    color: #33ff33; /* Neon Green Text */
    cursor: pointer;
    transition: background-color 0.3s, color 0.3s;
}

.button:hover {
    background-color: #33ff33; /* Neon Green Background */
    color: #0a0a0a; /* Dark Text */
}

/* Ensure you apply the 'button' class to both the start and restart buttons in your HTML */