Update login.html

netbox/templates/login.html

@@ -3,7 +3,7 @@
 
 {% block content %}
 <div class="row" style="margin-top: 150px;">
-    <div class="col-md-4 col-md-offset-4">
+    <div class="col-sm-4 col-sm-offset-4">
         {% if form.non_field_errors %}
             <div class="panel panel-danger">
                 <div class="panel-heading"><strong>Errors</strong></div>