<thead class="sticky-top table-dark">
  <tr>
    <form method="post">
      <th>
        <button class="p-0 text-white fw-bold text-nowrap btn btn-link arrow-<?= $number ?>" name="number" value="<?= $number == "up" ? "down" : "up" ?>" title="<?= $number == "up" ? "Abwärts sortieren" : "Aufwärts sortieren" ?>">#</button>
      </th>
      <th>
        <button class="p-0 text-white fw-bold text-nowrap btn btn-link arrow-<?= $article ?>" name="article" value="<?= $article == "up" ? "down" : "up" ?>" title="<?= $article == "up" ? "Abwärts sortieren" : "Aufwärts sortieren" ?>">Name</button>
      </th>
      <th>
        <button class="p-0 text-white fw-bold text-nowrap btn btn-link arrow-<?= $price ?>" name="price" value="<?= $price == "up" ? "down" : "up" ?>" title="<?= $price == "up" ? "Abwärts sortieren" : "Aufwärts sortieren" ?>">Price per Unit</button>
      </th>
    </form>
  </tr>
</thead>