Phone border

Hi Everyone... I am trying to build a faux app. I would like to minimize the border area (attached images). Is there a way to do that? 

I have the resolution set to portrait at 9:16 with a W: 540 px and H: 960px.  I have tried increasing those numbers but it doesn't help... makes it worse if you go too high.

I have included the Review link and .story file.  I appreciate any help with this project.

https://360.articulate.com/review/content/fa9aec6a-5e38-4d3c-b349-bd530983b481/review