Include index page into improved legibility

Signed-off-by: Jim Martens <github@2martens.de>

_assets/css/critical.scss

@@ -111,7 +111,7 @@ blockquote {
 
 // limit width of article to optimise reading experience
 @include media-breakpoint-up(md) {
-  article {
+  article, .index {
     width: 550px;
     margin-left: auto;
     margin-right: auto;

index.html

@@ -3,14 +3,15 @@ layout: default
 sidebarboxes: author encrypted-communication events
 ---
 
-<h1>2martens.de</h1>
+<div class="index">
+    <h1>2martens.de</h1>
 
-<p>
+    <p>
         Welcome on my personal website. This home page gives you an overview over all recently posted posts. To see
         the full list, visit the respective page (Speeches, Politics, Politics/G20, Computer Science, Blog, About).
-</p>
+    </p>
 
-<ul class="post-list list-unstyled">
+    <ul class="post-list list-unstyled">
         {% for post in site.posts limit:5 %}
         <li class="mb-4">
             <div class="small text-muted">
@@ -25,4 +26,5 @@ sidebarboxes: author encrypted-communication events
             </p>
         </li>
         {% endfor %}
-</ul>
+    </ul>
+</div>