Checkout form formatting (text input fields not in line)

http://funkitupdance.com/wp-content/uploads/2016/04/Screen-Shot-2016-04-19-at-21.36.12.png

Here’s a screenshot of my checkout form. The text input fields are not in line and I want to put them in line. Don’t want to mess with the plugin css and anything I add to the theme stylesheet doesn’t seem to do anything.

The theme that’s being used is a custom theme made by a developer and I’m just adding the shop.

Please help.

https://wordpress.org/plugins/woocommerce/