I found this application called ZCStyles ( https://creator.zoho.com/public/showAppInfo?ownername=srhyne&callbackUrl=zcstyles) and tried using it. But,  noticed that the <style type="text/css"> tags got wiped the next time I opened the note. Maybe that's a bug? Could you please guide a little how to use this application?

Could you please guide on changing the theme of my application? I have my own theme and want to customize the application's look and feel.