Add some margin

portal/layouts/article/single.html

 {{ partial "head.html" . }}
 
-<main>
-<section>
-    <header>
-    <h1>{{.Title}}</h1>
-    </header>
+<div class="container">
+    <main>
+    <section>
+        <header>
+        <h1>{{.Title}}</h1>
+        </header>
 
-    <article>
-    {{.Content}}
-    </article>
+        <article>
+        {{.Content}}
+        </article>
 
-    <footer>
-            <ul>
-                {{ with .PrevInSection }}<li><a href="{{ .Permalink }}">&laquo; {{ .Title }}</a></li>{{ end }}
-                {{ with .NextInSection }}<li><a href="{{ .Permalink }}">{{ .Title }} &raquo;</a></li>{{ end }}
-            </ul>
-    </footer>
-</section>
-<aside>
-    <ul>
-    <li><a href="{{ .Site.BaseURL }}">Home</a></li>
-    <li><a href="{{ "posts/" | absURL }}">Posts</a></li>
-    <li><a href="{{ .Section | absURL }}">Articles</a></li>
-    </ul>
-</aside>
-</main>
+        <footer>
+                <ul>
+                    {{ with .PrevInSection }}<li><a href="{{ .Permalink }}">&laquo; {{ .Title }}</a></li>{{ end }}
+                    {{ with .NextInSection }}<li><a href="{{ .Permalink }}">{{ .Title }} &raquo;</a></li>{{ end }}
+                </ul>
+        </footer>
+    </section>
+    <aside>
+        <ul>
+        <li><a href="{{ .Site.BaseURL }}">Home</a></li>
+        <li><a href="{{ "posts/" | absURL }}">Posts</a></li>
+        <li><a href="{{ .Section | absURL }}">Articles</a></li>
+        </ul>
+    </aside>
+    </main>
+</div> <!-- /container -->
 
 {{ partial "foot.html" .}}