I've tried re-styling the input fields of the square up module as it says here https://www.zen-cart.com/content.php...s-for-Zen-Cart

"The styling of the Square input fields is different from the rest of my payment input fields."
The module contains some CSS markup in the very bottom of the /includes/modules/pages/checkout_payment/jscript_square.php file, intended to create uniformity for the custom fields Square creates. For 99% of stores you will NOT need to change this; but in rare cases you may want to alter this CSS slightly to suit your needs.

However it is not seeing the updated styles?

My styles are below:

HTML Code:
<style title="square styles">.paymentInput {display:inline;font-size:1em;margin:0 0.1em 10px 0;height:35px;padding-left:5px;width:50%;border-style:solid;border-radius:3px;border-color:#333333;border-width:1px;}.paymentInput {background-color: white;border-style:solid;border-radius:3px;border-color:#333333;border-width:1px;}.paymentInput--error {color: red; border-color: red;}</style>