blog/themes/chosto/layouts/partials/header.html

<header>
  <section class="hero is-primary is-medium">
    <div class="hero-body has-text-centered">
      <p class="title">{{ .Title }}</p>
      {{ with .Params.subtitle }}
        <p class="subtitle">{{ . }}</p>
      {{ end }}
    </div>
  </section>
</header>