_includes/hero.html

<section class="hero {% if page.hero_height %} {{ page.hero_height }} {% else %} is-medium {% endif %} is-bold is-primary" {% if page.hero_image %} style="background: url('{{ page.hero_image }}') no-repeat center center; background-size: cover;" {% endif %}>
    <div class="hero-body">
        <div class="container">
            <p class="title is-2">{{ page.title }}</p>
            <p class="subtitle is-3">{{ page.subtitle }}</p>
        </div>
    </div>
</section>