body {
    font-family: sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f0;
    margin: 0; /* Reset default body margin */
    touch-action: manipulation; /* Prevent double-tap zoom */
}

.container {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    text-align: center;
    width: 90%; /* Adjust container width for smaller screens */
    max-width: 600px; /* Limit container width on larger screens */
}

#board {
    display: grid;
    grid-template-columns: repeat(4, 1fr); /* Use fr units for flexible sizing */
    grid-template-rows: repeat(4, 1fr); /* Use fr units for flexible sizing */
    gap: 5px;
    margin: 20px auto;
    width: 100%; /* Make the board fill the container */
    max-width: 400px; /* Limit board width on larger screens */
    height: auto; /* Adjust height automatically */
}

.tile {
    background-color: #4CAF50;
    color: white;
    font-size: 24px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    border-radius: 4px;
    transition: all 0.2s ease-in-out;
    width: 100%; /* Make tiles fill their grid cells */
    height: 100%; /* Make tiles fill their grid cells */
    aspect-ratio: 1 / 1; /* Make tiles square */
}

.tile:hover {
    background-color: #388E3C;
}

.empty {
    background-color: #fff;
    border: 1px solid #ccc;
}

.info {
    margin-top: 20px;
}

.info p {
    margin: 5px 0;
}

#reset-button {
    background-color: #2196F3;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

#reset-button:hover {
    background-color: #1976D2;
}

.game-message {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
    text-align: center;
}

/* Media query for smaller screens (e.g., smartphones) */
@media (max-width: 480px) {
    .container {
        width: 100%; /* Make container full width */
        padding: 10px;
    }

    #board {
        max-width: 100%; /* Make board full width */
    }

    .tile {
        font-size: 18px; /* Reduce font size on smaller screens */
    }
}