Different colored backgrounds

Site URL: https://www.sofijarart.com

I want to have different colored background for each indivduaal page on my website, specifically the pages that conform an index.  I understand that it is not possible through the template but that it is through editing the code. I am using the template Henson from the Tremont family (https://support.squarespace.com/hc/en-us/articles/227024467). When ever I change the color of my background it changes for all the pages on my website. 

I believe you should be able to set the background to an image. If so, couldn't you create a flat png of the color you want and set it as the background?