Use default flex layout for lists

layouts/_default/list.html

@@ -1,18 +1,15 @@
 {{ define "main" }}
-  <article class="cf pa3 pa4-m pa4-l">
-    <div class="measure-wide-l center f4 lh-copy nested-copy-line-height nested-links nested-img mid-gray">
-      {{ .Content }}
-    </div>
-  </article>
-  <div class="mw8 center">
-    {{ $paginator := .Paginate (where .Data.Pages "Section" .Section) }}
+  <article class="pa3 pa4-ns nested-copy-line-height nested-img">
+  <main class="cf ph3 ph5-l pv3 pv4-l f4 tc-l center measure-wide lh-copy mid-gray">
+    {{- .Content -}}
+  </main>
     <section class="flex-ns flex-wrap justify-around mt5">
-      {{ range  $paginator.Pages }}
-        <div class="relative w-100  mb4 bg-white">
-          {{ partial "summary.html" . }}
+      {{ range .Paginator.Pages }}
+        <div class="relative w-100 w-30-l mb4 bg-white">
+          {{- partial "summary.html" . -}}
         </div>
       {{ end }}
     </section>
-  {{ template "_internal/pagination.html" . }}
-  </div>
+    {{- template "_internal/pagination.html" . -}}
+  </article>
 {{ end }}