Virtue/Woocommerce checkout page CSS question

Hi,

This seems to be simple, but for me it isn’t… 🙁

Can anyone please tell me how I can change the padding on this input field on my check-out page?

<input style=”font-size: 1.5em; padding: 8px;” id=”cielo-card-expiry” name=”cielo_credit_expiry” class=”input-text wc-credit-card-form-card-expiry” autocomplete=”off” placeholder=”MM/AAAA” type=”tel”>

I’m completely lost and don’t know anything about CSS, also, I’m not sure who (as in: Virtue, WC or my WC credit card plugin) tells it to be 8 px…

Can I add some code to Theme Options > Advanced > Custom CSS?

Thanks a lot!!