Better styling for the aside

src/blog/index.html

@@ -9,7 +9,7 @@ pagination:
 <main class="wrapper-md stack-lg">
     <h1>Blog posts</h1>
 
-    <aside class="text-center">
+    <aside class="inverse text-center">
         <p>
             Subscribe via <a href="/rss.xml">RSS</a>, <a href="/atom.xml">Atom</a>, or <a href="/feed.json">JSON</a>.
         </p>