Is There a Way to Personalize Blog Posts with Code?

Hey. I'm creating a website based on blog posts and I've been customizing all my blog posts with the built-in features Squarespace offers, but I have not found a feature that allows me to use the color scheme I want. I'm looking to create something similar to the photos I've attached below where the main part of the post (Title, image, subtitle, etc.) has a black background, while the whole body of the post has white background. Is there a way to create this with code? Thanks in advance. 

Desktop view:

Mobile View: 

Hi,

I think this will require some custom code. Can you share link to a blog post on your site & link to example site? We can check easier