hack.hbs

{{page-layout }}
   {{#each layoutRow as |row|}}
      {{layout-row style=row.style}}
        {{cards-layout}} 
      {{/layout-row}}
   {{/each}}
{{/page-layout}}

{{page-layout-editor }}
   {{#each layoutRow as |row|}}
      {{layout-row-editor style=row.style}}
        {{cards-layout-editor}} 
      {{/layout-row-editor}}
   {{/each}}
{{/page-layout-editor}}

---
<div class="layout">
   <div class="layout-row" style="background:red">
        <div class="container-fluid">
          <div class="row">
            <div class="col-md-4">..card...</div>
            <div class="col-md-4">..card...</div>
            <div class="col-md-4">..card...</div>
          </div>
          <div class="row">
             <div class="col-md-12">..card...</div>
          </div>
        </div>
      </div
    </div>