Target input text fields by name?

I have some code which is not created by me. It comes from a credit card service. The text input fileds for cc number, expiry date month/Year and CCV all have the same class. They do have different names.
I need to change the width of the month / year fileds so that the fit next to each other. A little more CSS may be needed too. The problem is they all have the same class so I can’t use that to affect only 2. Can I use the name?

<input class="intra-field-label" type="text" name="expiry[month]" maxlength="2" value="" size="2">
<input class="intra-field-label" type="text" name="expiry[year]" value="" maxlength="2" size="2">

Also even if I do change the size of all of them they change back when they ge focus. What causes that and how do I fix it?
If you want to see it in action go here (no I did not design it!)
Add it to the cart, proceed to checkout and look at the bottom of the checkout page.
Please click remove for the product when you leave

The class attribute can have multiple class names within the quotes just separate them by a space. For example

class=“intra-field-label removespacing”

this looks like a job for the attribute selector (If you dont need to support IE6) !