Better button layout on error page

public/css/vroom.css

@@ -257,6 +257,9 @@
   text-align: justify;
   text-justify: inter-word;
 }
+.btn-full {
+  width: 100% !important;
+}
 html,
 body {
   height: 100%;

templates/default/error.html.ep

@@ -5,16 +5,19 @@
   <div class="jumbotron alert-danger">
     <h2><%=l 'ERROR_OCCURRED' %></h2>
     <p><%= $msg %></p>
-    <div class="btn-group">
-      <a class="btn btn-primary btn-lg" role="button" href="<%= $self->get_url('/') %>"><%=l 'BACK_TO_MAIN_MENU' %></a>
+    <div class="row">
+      <div class="col-sm-6 col-lg-4 col-xl-3">
+        <a class="btn btn-primary btn-lg btn-full" role="button" href="<%= $self->get_url('/') %>"><%=l 'BACK_TO_MAIN_MENU' %></a>
+      </div>
+      <div class="col-sm-6 col-lg-4 col-xl-3">
         <% if ($err eq 'ERROR_NAME_CONFLICT'){ %>
-      <a class="btn btn-default btn-lg" role="button" href="<%= $self->get_url('/') . $room %>"><%=l 'JOIN_THIS_ROOM' %></a>
+        <a class="btn btn-default btn-lg btn-full" role="button" href="<%= $self->get_url('/') . $room %>"><%=l 'JOIN_THIS_ROOM' %></a>
         <% } elsif ($err eq 'WRONG_PASSWORD'){ %>
-      <a class="btn btn-default btn-lg" role="button" href="<%= $self->get_url('/password') . '/' . $room %>"><%=l 'TRY_AGAIN' %></a>
+        <a class="btn btn-default btn-lg btn-full" role="button" href="<%= $self->get_url('/password') . '/' . $room %>"><%=l 'TRY_AGAIN' %></a>
         <% } elsif ($err eq 'ERROR_ROOM_s_LOCKED' && stash 'ownerPass'){ %>
-      <a class="btn btn-default btn-lg" role="button" href="<%= $self->get_url('/password') . '/' . $room %>"><%=l 'AUTH_IF_OWNER' %></a>
+        <a class="btn btn-default btn-lg btn-full" role="button" href="<%= $self->get_url('/password') . '/' . $room %>"><%=l 'AUTH_IF_OWNER' %></a>
         <% } elsif ($err eq 'ERROR_ROOM_s_DOESNT_EXIST'){ %>
-      <button class="btn btn-default btn-lg" type="submit" form="createRoom"><%=l 'CREATE_THIS_ROOM' %></button>
+        <button class="btn btn-default btn-lg btn-full" style="width: 100%" type="submit" form="createRoom"><%=l 'CREATE_THIS_ROOM' %></button>
       <% } %>
     </div>
     <% if ($err eq 'ERROR_ROOM_s_DOESNT_EXIST'){ %>