Additional styles for co-op content

This makes links visible and improves the display of blockquotes in
the co-op boxes.

_layouts/coop.html

@@ -19,7 +19,9 @@
         <h2>{{ page.name }}</h2>
 
         <p><strong>About this co-operative</strong></p>
-        {{ content }}
+        <div class="coop-info-box__body stack">
+          {{ content }}
+        </div>
 
         <p><strong>Co-operative website</strong></p>