Articulate's Custom Click and Reveal Template

I came across this post by Articulate staff member Nicole Legault > https://community.articulate.com/e-learning-examples/click-and-reveal-template-with-motion-for-storyline-2?page=2#comments.

Since Nicole posted this lovely template two years ago,  I'm not sure if she is still checking replies/messages.  I am hoping someone can help me out with my question as I'm up against a very tight deadline (see below and thanks!):

I am so glad that I discovered this post--this is a great interaction--thank you! I am building a course that already has about 70 slides/pages, and I have already incorporated Nicole's template. Purple is my favorite color, however the template doesn't match the color scheme of my course. Despite looking at all of the objects in the Timeline, I cannot figure out how to access the purple rectangle that is in the background (not to be confused with the purple border, which I am able to access). Any help in this area would be greatly appreciate!