404 page

404 Block

you need to add the class is-fullheight to section hero

The hero body block need to go just before the the closing hero </section>

      <div class="hero-body">
      <div class="container error-page has-text-centered">
        <h1 class="title">404
        </h1>
        <h4 class="subtitle">You ventured some where no one as ever ventured before ?
        </h4>
      </div>
    </div>