Placeholder css

I want to style the card input placeholder…

Having looked at the Stripe.js docs I have managed to figure out how to change two js files inside the plugin assets. But I would rather have custom css so that when the plugin gets updated, the styles don’t change with it.

But I have no way of figuring out the css except inside the javascript files. The issue of styling the input field has been asked before, but the recommended css does not work for the placeholder text.

Any pointers?