title: Where are these scss functions defined in the Bigcommerce Stencil stack?
body: <p>I'm looking through the source for a store using Bigcommerce's default Stencil theme. In an SCSS file I see functions being used, but I'm not sure where these functions are defined. For example:</p>
  
  <pre><code># assets/scss/layouts/footer/_footer.scss
  
  .footer {
      background-color: $footer-background;
      border-top: container("border");
      padding: spacing("double") 0;
  }
  </code></pre>
  
  <p>I can't find where this <code>container</code> or <code>spacing</code> methods are coming from? Are these part of scss? Part of <a href="http://foundation.zurb.com/sites.html" rel="nofollow">Foundation</a>? Or maybe something Bigcommerce has defined in their <a href="https://github.com/bigcommerce-stencil/citadel" rel="nofollow">Citadel</a> library?</p>