SharePoint Online-Communication Site-Not able to achieve this color scheme

[Ricky Raghavan]

I am trying to achieve the color scheme described below. The modern "Change the Look" allows one to customize colors but doesn't allow us to add a background Image which the classic "Change the look" supports. The Classic "Change the Look" doesn't have a color palette with a white Header and a dark body. I tried following this blog https://blog.pixelmill.com/3348/changing-colors-modern-site/about adding a custom Theme via Powershell, but it doesn't allow you to add an Image.

As mentioned in the diagram, I would also like to add a layer of color over the Top Nav.

How can I achieve the color scheme mentioned below?

[#2]

>doesn't allow us to add a background Image 

IMHO this is a style that hasn't been mainstream for over a decade. More often than not it looks awful and sometimes can make the text on the page more difficult to read. Very unlikely this will be an OOTB option for Modern Pages.