diff --git a/app/logical/anonymous_user.rb b/app/logical/anonymous_user.rb
index 4cc921903..0a6125bb3 100644
--- a/app/logical/anonymous_user.rb
+++ b/app/logical/anonymous_user.rb
@@ -218,7 +218,7 @@ class AnonymousUser
   end
 
   def custom_style
-    nil
+    ""
   end
 
   def show_deleted_children?
diff --git a/app/views/users/custom_style.css.erb b/app/views/users/custom_style.css.erb
index b074d59cd..01e8ede86 100644
--- a/app/views/users/custom_style.css.erb
+++ b/app/views/users/custom_style.css.erb
@@ -1,4 +1,4 @@
-<% CurrentUser.user.custom_style.split(/\r\n|\r|\n/).each do |line| %>
+<% CurrentUser.user.custom_style.to_s.split(/\r\n|\r|\n/).each do |line| %>
   <% if line =~ /^@import/ %>
     <%= raw(line) %>
   <% else %>