Submit button different size in preview form mode vs edit

I have a form where the submit button is the correct size in edit mode but it is a very different size when in preview mode.  why?

I keep changing the width and nothing changes.

I see that you have already added the code, please add !important property to make the code work. Alternatively, you can just add the code below:

.form-submit-button{

  width: 250px !important;

}

Thank you ... that fixed it.