has-large-font-size
Preset size
<nav class="has-small-font-size wp-block-navigation alignwide">
<ul>
<li class="wp-block-navigation-link">
<a class="wp-block-navigation-link__content has-small-font-size has-text" href="" title="About The Tests">About The Tests</a>
</li>
<li class="wp-block-navigation-link">
<a class="wp-block-navigation-link__content has-small-font-size has-text" href="" title="A Parent Page [OLD]">A Parent Page [OLD]</a>
</li>
</ul>
</nav>custom font size
<nav class="wp-block-navigation alignwide" style="font-size: 19px;">
<ul>
<li class="wp-block-navigation-link">
<a class="wp-block-navigation-link__content has-text" style="font-size: 19px;" href="" data-title="About The Tests">About The Tests</a>
</li>
<li class="wp-block-navigation-link">
<a class="wp-block-navigation-link__content has-text" style="font-size: 19px;" href="" data-title="A Parent Page [OLD]">A Parent Page</a>
</li>
</ul>
</nav>color setting
note is-style-dark