.sudoku-table {
    border-collapse: collapse;
    margin: 20px auto;
    font-size: 18px;
}

.sudoku-td {
    border: 1px solid black;
    text-align: center;
}

.sudoku-input {
    text-align: center;
    font-size: 15px;
    border: none;
    width: 100%;
    aspect-ratio: 1 / 1;
}

.sudoku-td:nth-child(3),
.sudoku-td:nth-child(6) {
    border-right: 3px solid black;
}

.sudoku-tr:nth-child(3) .sudoku-td,
.sudoku-tr:nth-child(6) .sudoku-td {
    border-bottom: 3px solid black;
}

.sudoku-table {
    border: 3px solid black;
}