improve spacing of author section

_layouts/post.html

@@ -85,7 +85,7 @@ <h1 class="header-post-title">{{ page.title }}</h1>
       <div class="col-md-12 col-lg-8">
         {% include shared/_post_author.html %}
         {% if page.co_author %}
-          <div class="mt-4">
+          <div class="mt-5">
             {% include shared/_post_author.html author=co_author %}
           </div>
         {% endif %}