Atwood, Bradbury, and Donham theme ebook CSS does not display in Adobe Digital Editions ebook reader

[mcgratay]

Prerequisites

• [x] Can you reproduce the behavior you wish to address with all plugins except Pressbooks deactivated?
• [x] Are you running the latest version of Pressbooks, the latest version of McLuhan, and the latest version of WordPress?
• [x] Are you experiencing the issue while using this book theme?
• [x] Did you perform a cursory search to see if your bug or enhancement is already listed?

Description

Some themes' ebook CSS is not compatible with common ebook reader software Adobe Digital Editions. These same EPUB files display fine in Calibre or iBooks, but all fonts, design elements, and image classes are removed when viewed on ADE. The following screenshot shows an image that is bleeding over onto the next page and overlapping the text.

MOBI, PDF, and web formats seem unaffected. Issue only appears in Atwood, Bradbury, and Donham so this is not a Buckram-related issue.

Example: https://ebookimagesizing.textopress.com/

There is no available specifications requirement document for Adobe Digital Editions; ADE should be compatible with any files that meet IDPF global standards. This bug is not resulting in any validation error as interpreted by Pressbooks during the export process.

Steps to Reproduce

1. Go to Appearance > Themes and select the Atwood, Bradbury, or Donham theme
2. Export to EPUB and download
3. Open file in Adobe Digital Editions

Expected behavior: Theme styles display in all common ebook reader platforms

Actual behavior: CSS for the Atwood, Bradbury, and Donham themes is not compatible with Adobe Digital Editions

[SteelWagstaff]

@mcgratay do you have a way to report this upstream to Adobe or at least post about it in their forums? That'd be my recommended first step.