How to center form fields and set them the same width?

Is there a way to make both fields even size?

And center inside the gray box?

https://www.jotform.com/build/70385679373166

Help! :/

You may try injecting this CSS code to your form: 

li#id_2, li#id_3{

 width: 50% !important ;

}

This will display the fields centered already, you could see it on this cloned form of yours: https://form.jotform.com/70387236377969 

This guide will help you to inject the given code: https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes 

Hope this helps.