Preview app

Hello everyone

The white color affects my eyes and causes eye strain, I could not change the background color of The Preview app while reading a pdf. Generally, is it possible to change its color?

For example, when you read a book in the Book app on Macbook you can change the background color to gray, light brown, black, etc. I want to have these colors in the Preview too.

Also, It seems that we cannot change the format of PDF files to Electronic publication (epub) on Mac, if I could do this, at least I can read PDFs in the Book app, do you know how is that possible?

I appreciate any advice and alternative apps.