Change Survey Results slide to custom background image (HTML)

Hey there,

Is anyone really good at HTML formatting?

I have a Storyline block to collect results from a set of questions -built in Storyline, not QuizMaker, as a Survey.

The results slide (default) is a basic table on a white screen. I have a custom PNG I want to add behind this table. Below is a screenshot of how far I could get with my limited knowledge. I realize that my PNG is not acting like a background image so the table can lay on top. 

Articulate support has been awesome, but this is beyond their scope. Anyone here really good at HTML that can offer some advice?

Sincerely,

Kevin