For self-publishers, a professionally formatted ePub is non-negotiable. The core challenge is reflowable text—content that adapts seamlessly to any screen size, from a phone to an e-reader. While AI tools accelerate conversion, human oversight is essential for quality. Here’s how to leverage AI automation while ensuring technical perfection.
Semantic Foundation & Mobile-First CSS
Instruct your AI tool to “Convert this DOCX to ePub3 with semantic HTML and a mobile-first CSS.” This means using proper Heading 1, 2, 3 tags for structure—never manual formatting. Start your CSS with a reset to normalize margins and use relative units like rem and em. Avoid fixed commands like font-size: 12pt; margin-left: 50px; Instead, use fluid styles: font-size: 1rem; margin-left: 2em;.
Handling Images & Complex Layouts
AI can insert images, but you must verify the code. Ensure all images have max-width: 100% and are wrapped in <figure> tags with <figcaption>. Be wary of complex layouts: a floated image at a chapter’s end can cause the next heading to wrap awkwardly. Always add descriptive Alt Text in your source document. Remember, many reading systems strip background colors and images, so never rely on them for crucial information.
The Critical Validation Checklist
Post-conversion, rigorous testing is key. Use this AI-informed checklist:
- Navigation: Validate that the NCX/nav document matches all Heading 1-3 styles. Click every TOC link.
- Internal Links: Test all cross-references (“See Chapter 5”) and footnote “Back” buttons.
- Styling: Do drop caps using
::first-lettercause issues? Avoid manual tabs or text boxes. - Reflow Test: Change the font size. Change the font family. Rotate the screen. Is it still a beautiful, readable experience?
Multi-Device Testing Workflow
Automation doesn’t replace device testing. Use tools like Reedsy Editor for instant previews. Then, test physically: open it in Apple Books on an iPad, send the .epub to your Kindle via “Send to Kindle,” and, if possible, test on a Kobo or Nook app. This reveals rendering quirks no simulator can.
For a comprehensive guide with detailed workflows, templates, and additional strategies, see my e-book: AI-Assisted E-book Formatting for Self-Publishers.