Bootstrap - Duas regiões lado a lado e um botão centralizado

<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap Example</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet">
  <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"></script>
  <style>

  .custom-height {
    height: 500px;
  }
  .custom-bg1 {
    background-color: #0af1b3;
  }
  .custom-bg2 {
    background-color: #fc8d16;
  }

  </style>
</head>
<body>

<div class="container-fluid">
  <h1>Testing the Grid</h1>
  <div class="row">
    <div class="col-4 offset-1 custom-height custom-bg1">
      <!-- Conteúdo da primeira região -->
    </div>
    <div class="col-4 offset-2 custom-height custom-bg2">
      <!-- Conteúdo da segunda região -->
    </div>
  </div>

  <div class="row mt-5">
    <div class="col-4 offset-4">
      <div class="d-grid">
        <button class="btn btn-primary btn-lg">Botão</button>
      </div>
    </div>
  </div>

</div>

</body>
</html>