Fix grid

Author: mrmrs

docs/layout/grid/index.html

@@ -183,7 +183,7 @@ <h2 class="f3 b">Example</h2>
           </div>
         </div>
       </section>
-      <div class="mt5 cf">
+      <div class="cf pa3 ph5-ns mv4 mv5-ns bt bb b--black-10">
         <div class="dib mr4">
           <h1 class="f6 fw6">Previous</h1>
           <a href="/docs/debug-grid/" class="link fw6 blue dim">Debug with a Grid</a>