Update Bootstrap

_layouts/default.html

@@ -8,7 +8,7 @@
     <main class="jumbotron">
       <div class="container-fluid large-header" id="large-header">
       <div class="row">
-        <div class="col text-center">
+        <div class="col-xs-12 text-center">
           <img src="{{ "/images/logo.svg" | prepend: site.baseurl }}" alt="Chaospott Logo" />
         </div>
       </div>