Studio: syncing up markup/styling for other 'learn more' external help links

cms/templates/textbooks.html

@@ -75,7 +75,10 @@ require(["js/models/section", "js/collections/textbook", "js/views/list_textbook
         <div class="bit">
           <h3 class="title-3">${_("What if my book isn't divided into chapters?")}</h3>
           <p>${_("If your textbook doesn't have individual chapters, you can upload the entire text as a single chapter and enter a name of your choice in the Chapter Name field.")}</p>
-          <p><a href="${get_online_help_info(online_help_token())['doc_url']}" target="_blank">${_("Learn More")}</a></p>
+        </div>
+
+        <div class="bit external-help">
+          <a href="${get_online_help_info(online_help_token())['doc_url']}" target="_blank" class="button external-help-button">${_("Learn More")}</a>
         </div>
       </aside>
     </section>