How to change hint text in Snipcart's payment form

Question

I am using snipcart in my react web app. Reading their docs I found out that I cannot override the css of the payment form because that payment form is being loaded in an iframe and to customize it , I have to use their javascript sdk like this:

 Snipcart.api.theme.customization.registerPaymentFormCustomization({
                label: {
                    color: '#fff',
                },
                legend: {
                    color: '#fff'
                },
            });

Now this is working great for legend and label elements, but there's one paragraph in snipcart form as well which has class test-card-hint. And I can't find any way to override it. I have tried passing down following values:

 Snipcart.api.theme.customization.registerPaymentFormCustomization({
                label: {
                    color: '#fff',
                },
                legend: {
                    color: '#fff'
                },
                p:{
                   color:"#fff"
                }
            });

 Snipcart.api.theme.customization.registerPaymentFormCustomization({
                label: {
                    color: '#fff',
                },
                legend: {
                    color: '#fff'
                },
                ".test-card-hint":{
                    color: '#fff'
                 }
            });

Also tried using sibling selector like legend ~ p but to no avail.

You can see in the image below that only styles for label and legend are being generated.

Here is the html markup for the form:

Does anyone know of a workaround to this? Is it possible to override css for this particular element at all?