<?php
defined('BASEPATH') OR exit('No direct script access allowed');
?>
<style>
    table input {
        border: 1px solid rgba(0, 0, 0, 0.25);
        width: 50px;
        height: 50px;
        font-size: 50px;
    }
    .row-2, .row-5 {
        border-bottom: 1px solid rgba(0, 0, 0, 0.75);
    }
    .col-2, .col-5 {
        border-right: 1px solid rgba(0, 0, 0, 0.75);
    }
</style>
<section class="container">
    <div class="row">
        <form method="post">
            <table>
                <?php for($i = 0; $i < 9; $i++) { ?>
                    <tr class="row-<?= $i; ?>">
                    <?php
                    for ($j=0; $j < 9; $j++) {
                        ?>
                        <td class="col-<?= $j; ?>">
                            <input type="text" maxlength="1" name="field-<?= $i; ?>-<?= $j; ?>">
                        </td>
                        <?php
                    }
                    ?>
                    </tr>
                    <?php
                } ?>
            </table>
            <input type="text" name="sudoku" value="true" style="display:none">
            <input type="submit" name="submit" class="btn btn-primary" value="Absenden">
        </form>
    </div>
</section>