Set the float: left style on the 'Older Posts' button so the pagination buttons are drawn with the same height

static/stylesheet/style.less

@@ -290,6 +290,10 @@ a.btn:hover {
   display: block;
 }
 
+.float-left {
+  float: left;
+}
+
 .float-right {
   float: right;
 }

templates/partial/pagination.html

@@ -1,7 +1,7 @@
 {% if DEFAULT_PAGINATION %}
   <div class="pagination">
   {% if articles_page.has_next() %}
-    <a class="btn" href="{{ SITEURL }}/{{ articles_next_page.url }}">
+    <a class="btn float-left" href="{{ SITEURL }}/{{ articles_next_page.url }}">
       <i class="fa fa-angle-left"></i> {{ _('Older Posts') }}
     </a>
   {% endif %}