I have a title and a div horizontally, what I am trying to do is to center the div with the corresponding title.

enter image description here

As can be seen in the image, it cannot be centered properly.

This is my code:

<h1 id='<?= str_replace(" ", "", $data->title); ?>'><?= $data->title; ?></h1>
<?= $data->text; ?>

<div class="flexbox">
  <div class="contenido-flex">
    <blockquote>
      <p><?= $data->title; ?></p>
    </blockquote>
    <pre class="is-paddingless" id="a<?= esc($data->id); ?>"><code class="<?= strtolower($data->tip); ?>">
          <?php if ($data->fdc== "JSON") : ?>
          <?= json_decode($data->cod); ?>
          <?php else : ?>
             <?= $data->cod; ?>
          <?php endif; ?>  
          </code></pre>
  </div>
</div>




.flexbox {
    /*  */
    height: 100vh;
}

.contenido-flex {
    margin-top: -700px;
}