There are plenty of ways to do this. You have to use custom CSS no matter what. In my example, I set the .ui-block-a and .ui-block-b to be a new width. I wouldn't do this, I just wanted to show as an example. What I would do is add another class (example class="phoneinput") and change the width of that and apply the class to the div OR the input. I would like you to try it out yourself :-)