Prettify billing page

app/dashboard/templates/dashboard/billing.html

@@ -8,12 +8,12 @@
 {% endblock %}
 
 {% block default_content %}
-  <div class="row">
-    <div class="col-md-8 offset-md-2">
-      <h1> Billing </h1>
+  <div class="bg-white p-6" style="max-width: 60em; margin: auto">
+    <h1 class="h3 mb-5"> Billing </h1>
 
     <p>
-        You are on the <b>{{ current_user.get_subscription().plan_name() }}</b> plan. Thank you very much for supporting SimpleLogin. 🙌
+      You are on the <b>{{ current_user.get_subscription().plan_name() }}</b> plan. Thank you very much for supporting
+      SimpleLogin. 🙌
     </p>
 
     {% if sub.cancelled %}
@@ -34,9 +34,6 @@
         <a class="btn btn-warning" href="{{ sub.cancel_url }}"> Cancel subscription 😔 </a>
       </div>
     {% endif %}
-
-    </div>
-
   </div>