Using the .title and .subtitle element classes gives greater control over the ranking and appearance of headings by making HTML markup independent of font-size rendering. With Bulma CSS, size modifier classes can be used to set different title and subtitle sizes for different parts of a page.
Construct a subtitle heading
"My Subtitle"
|> Ui.Element.subtitle "h2"
|> Ui.Modifier.add "is-6"
|> Ui.render
--> <h2 class="subtitle is-6">My Subtitle</h2>
Construct a title heading
<h1>to<h6>, or<p>)