Running v 3.0.1, Mac OS. In compiling, I use the “as-is” templates for scenes and chapters with styles: no style (default) for regular paragraphs, modified with line spacing at 1.2; Flush Left - same formatting just left-indent = 0; and a Block Quote. When compiling to ePub3 or Mobi KF8, the line spacing for the style FLUSH LEFT does not format correctly when displayed in iBooks or Kindle reader. It uses a line height of 1.0 or 1.0 (cannot really tell, but clearly not 1.2). Default and block quote styles format correctly (1.2 line height). When compiled as ePub2/Kindle (older versions) the Flush Left style formats correctly. Not certain if the issue is with the readers or Scrivener. The output in the readers (wherever it originated from) is visually disruptive, so for now I am just using the older output versions.
It might be easier to see what is going on by using an ePub editor like Calibre’s, and verifying that your style blocks are configured correctly, rather than trying to guess at the problem through the lens of a consumer-oriented reading application or device. As you note, they may be well changing things on the fly to suit a particular look—the CSS is more a guideline for them to follow than a rigid set of instructions.
As for myself, if I create a style called “Block Quote” and a style called “Body Text” and save them both to 1.5 line height (I chose something obvious for testing purposes), then compile and examine the stylesheet.css file in Calibre, I see:
.body-text { margin: 0rem 0% 0rem 0rem; text-indent: 0rem; line-height: 1.5em; }
.-block-quote { margin: 0rem 0% 0rem 3rem; text-indent: 0rem; line-height: 1.5em; }
So both the body text style I applied to everything and the block quote style that I applied to a few test paragraphs are stipulating 1.5 line-height, and indeed I get a consistent output in iBooks as well. That would indicate you and I did something slightly differently in our compile settings, I copied what configuration you relayed, so the missing ingredient is something else.
It could be what you’ve called your styles even. If you go into the Styles compile format pane for the Format you are using and check the list, do you see style overrides in this pane that match the names of the styles you use? Perhaps you call your text style “Body”, which in the default “Ebook” Format is using a different line-height. Indeed if I change my style name to “Body” in the editor, I get your result, and this is the CSS I see:
.body { margin: 0rem 0% 0rem 0rem; text-indent: 0rem; }In other words, no line-height is defined, leaving that up to the reader (a generally good thing to do by the way).
If I delete the “Body” override in the compiler, then I get a consistent result again, as expected, because once again “.body” is driven entirely by my editor styles, not the compile settings.