Chrome Extension is being blocked by Etsy?

I’m trying to build a new chrome extension that adds a button to Etsy listing page.
The extension is unpacked, and once installed it works great on any site. however, whatever I tried – I’m not able to see the change on Etsy.

Here is the content script that runs:

document.body.appendChild( div );
div.appendChild( btnForm );
btnForm.appendChild( btn ); = 'myDivId'; = 'fixed'; = '50%'; = '50%'; = '100%'; = '100%'; = 'red';

Again, this works great on any other webpage I tested.
The permissions I’m using:

"permissions" : [