TNEW v7 Payment Screen Buy Now - Custom/Javascript Not Working

Hey I have been setting up TNEW v7 on our test site, and when I press the buy now button on the payment screen it isn't allowing me to override the default CSS of the modal that pops up

I noticed that the CSS for the modal on that page is coming from staging-na-payments.tnew.info rather than the tnew.scss files

https://staging-na-payments.tnew.info/css/bootstrap.forms.min.css

I even tried to fix it with some javascript:

var list = document.getElementsByTagName('button');
for(var i = 0; i < list.length; i++){
    if(list[i].innerText == "Complete Order"){
        list[i].id = "complete-order-fix";
        list[i].className = "";
        console.log(list[i].className + ". " + list[i].id + ". " + list[i].innerText);
    }
}

But that doesn't seem to be working either for some reason.

Is there something different I need to do with the CSS for the payment modal from the rest of the TNEW v7 pages?