Update style_controller.rb

app/controllers/extranet/style_controller.rb

 class Extranet::StyleController < Extranet::ApplicationController
+  skip_before_action :authenticate_user!, :authorize_extranet_access!
+  
   def index
     render body: current_extranet.css, content_type: 'text/css'
   end
-end
\ No newline at end of file
+end