body {
    font-family: Arial, sans-serif;
    text-align: center;
    margin: 20px;
}

#sudoku-container {
    display: grid;
    grid-template-columns: repeat(9, 40px);
    grid-template-rows: repeat(9, 40px);
    gap: 1px;
    justify-content: center;
}

.cell {
    width: 40px;
    height: 40px;
    text-align: center;
    font-size: 18px;
    border: 1px solid #ccc;
}

.cell:focus {
    border-color: #007bff;
    outline: none;
}

button {
    margin: 20px;
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
}

#message {
    font-size: 18px;
    margin-top: 10px;
    color: green;
}