converting from odt and background colour

Hello,

I'm trying to convert an odt document to mobi for kindle app android.
Both on kindle app and on the calible ebook viewer, I have issues with background colour when I set the reader (both kindle and calibre) to Sepia.

It looks like most of the text is with white background (wrong as it should be sepia), but some part of it is sepia.

You can see what I mean here:
https://imgur.com/a/QKmpvSL

How to fix it ?
I tried both converting to mobi and reading directly the odt from calibre, same thing

Thank you !
robse