You've poured your heart into your manuscript. You convert it to an ePub, only to find images overflowing on a phone or headings awkwardly wrapped on a tablet. The dream of a seamless reading experience shatters across a dozen different screens. The core principle to master is device-agnostic styling . Your CSS must create a beautiful, readable experience that reflows gracefully, regardless of the user's font size, screen orientation, or device. This is where AI automation becomes a powerful ally, not a replacement for your expertise. Think of AI as a meticulous junior developer who enforces best practices at scale. For instance, you can instruct an AI tool to: "Convert this DOCX to ePub3 with semantic HTML and a mobile-first CSS." This single directive sets the foundation for reflowability, prompting the AI to generate clean, structured code that adapts. Mini-Scenario: A client reports that chapter titles are cut off on their old Kobo.…