How do you change the window size of a field?

I know this has to be done by inserting a custom CSS in Form Styles under Preferences, but I can't figure out the CSS code to achieve what I want. 

I'm trying to have two address fields side-by-side, but the size of the form doesn't allow it, and I can't change the size of the form itself because it has to fit on the webpage which will be using it.

Enabling columns in the Designer should do that;

Otherwise, you can inject the following custom CSS to move the second address field to the left of the first address field:

li#id_3 {

    margin-left: -35px;

}

Again, here's how to inject the codes: https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes.