I created an InDesign book composed of documents that had had no paragraph or character styles in the palettes until text was copied over from a single overall document. I worked absolutely as clean as I could.
I synchronized the book to that single overall document several times, including immediately before exporting the book to epub. My export settings disallowed any local formatting. Character styles were restricted to one named "Italic" for which the only format applied was Italic in the Font Style field, and one named "Small Caps" for which NO formatting was included in the character style.
There was, as far as I can see, no reason for any character or paragraph styles to export to anything but identically-named CSS entries. That is to say, any text with the character style "Italic" applied in the InDesign doc should have output with the same text with a span class entry of "Italic" around it.
I still ended up with p and span CSS entries with extra numbers appended to them:
span.Italic {
font-style:italic;
font-weight:normal;}
span.Small-Caps-1 {
font-variant:normal;}
span.Italic-1 {
font-style:italic;
font-weight:normal;}
span.Small-Caps-2 {
font-variant:normal;}
span.Italic-2 {font-style:italic;
font-weight:normal;}
span.Small-Caps-3 {
font-variant:normal;}
span.Italic-3 {
font-style:italic;
font-weight:normal;}
and
p.x-SECTION-BREAK, p.x-SECTION-BREAK-1, p.x-SECTION-BREAK-2, p.x-SECTION-BREAK-3 and so on.
Why would the InDesign epub output engine choose to generate and apply new spans and paragraph-level styles, which multiply the complexity of editing the CSS directly? How can I prevent InDesign from doing this?