body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header, footer {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 10px 0;
}

main {
    padding: 20px;
}

#sudoku-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-gap: 2px;
    /* Additional styling */
}

/* Add more styles for cells, buttons, etc. */