The mzp-l-align-center class aligns buttons in the center.

<div class="mzp-c-button-container mzp-l-align-center">
    <button class="mzp-c-button" type="button">Primary</button>
    <button class="mzp-c-button mzp-t-secondary" type="button">Secondary</button>
    <p class="mzp-c-button-info">More information.</p>
</div>