E012 - Both inline and *_file forms specified

Cause

A slide element specifies both the inline form (markdown:, html:, mermaid:, iframe_html:) and the corresponding *_file: form (markdown_file:, html_file:, mermaid_file:, iframe_html_file:) for the same field. Only one of the pair may be set.

Example

{ markdown: "# inline", markdown_file: "intro.md" }

How to fix

Pick one form and remove the other. Use the inline form for short content; use the *_file form to keep large content out of the slide JSON.