[photoluminations]

This concerns a heavily illustrated kids' book of 130 "pages" for publication via Kindle system, specifically for the not-yet-seen FIRE color reader. The book depends on color for effect so the FIRE is the only target platform in Kindle universe.

I assume (perhaps foolishly)--OK, I hope-- that if a book reads OK in the KINDLEGEN, it will read on the FIRE.

I recognize that Calibre is NOT designed as a publishing tool, but what else is there? Sigil doesn't quite do the job. And Calibre does most of the needed conversion nicely.

I generate a well-formed epub from html and CSS. I feed the epub to KINDLEGEN using the Calibre settings for the KINDLE DX output profile; that succeeds to generate a MOBI file. The file reads well on the KINDLE VIEWER (but not so well on Kindle for PC).

QUESTION ONE: @rules, what is happening here, does it matter?

KINDLEGEN says this numerous times:
"Info(cssparser): @rules other than @import and@charset are not supported"
I assume these are rewrites of CSS rules to html??

QUESTION TWO: Adding additional metadata and guide info. I propose this method, will it work? other methods?

After I add the html file to Calibre, Calibre creates an OPF file and FILE.ZIP. I can open the OPF and do the following:

identify the cover in the metadata and the manifest.
reference in the guide: the html TOC, the cover, and the start reading location

QUESTION THREE: Best practices for images?

Since every time a jpeg image is modified it loses quality, some experts advise replacing all images with well-formed, pristine images in the final package. I think this can be done by giving each image the identifier name generated by Calibre and replacing the images in the Calibre output.