Apply max width to all input elements.

Update form class with better name and add form-conrainer--narrow class.

templates/applications/new/step_2.html

@@ -21,7 +21,7 @@
   </p>
   <hr>
   <application-environments inline-template v-bind:initial-data='{{ form.data|tojson }}'>
-    <form method="POST" action="{{ url_for('applications.update_new_application_step_2', portfolio_id=portfolio.id, application_id=application.id) }}" v-on:submit="handleSubmit" class="form">
+    <form method="POST" action="{{ url_for('applications.update_new_application_step_2', portfolio_id=portfolio.id, application_id=application.id) }}" v-on:submit="handleSubmit" class="form-container">
       <div class="subheading">{{ 'portfolios.applications.environments_heading' | translate }}</div>
       <div class="panel">
         <div class="panel__content">