Error: The tweakcn's live theme preview script could not be found. Please make sure the script is included in the website's source code and try again.

Greetings,

I am a bit lost. I don't believe this is an error, but I am wondering if anyone could point me to a right direction. I am using https://tweakcn.com/editor/theme?tab=typography&p=custom and having point it to my localhost:

However, I am not getting live preview of the style change. Instead, I am getting an error:

The tweakcn's live theme preview script could not be found. Please make sure the script is included in the website's source code and try again.

Am I supposed to download a script and placed it somewhere in my project ? I cannot find any guideline or reference (perhaps I am not looking at right places?)

Thanks in advance!!