In Bootstrap 4 vertical alignment (align-items) to the center does not work, why?

Question

Bootstrap

I did not find an answer to this question, here is the code

<div class="container">
  <div class="form__submit d-flex align-items-center">
    <a href="#" class="btn-lg btn btn-primary">Отправить</a>
    <p>Нажимая кнопку «Отправить», вы соглашаетесь с <a href="#">политикой обработки персональных данных</a></p>
  </div>
</div>

The button is still aligned to the top border (flex-start). What can be wrong? Code in the sandbox .
Thanks in advance.

Answer 1

Well, you have a parent element (.form_submit) with a height of 64 pixels - a button in the center. Make it taller and you'll see.
In this case, flex start and center are approximately equal.