Unfortunately, Amazon's products don't fully support the EPUB3 format (they always try to go their own way).
If you want users to set their own font size, you need to use reflowable EPUB. Fixed Format EPUB is to make the EPUB look as it does for a print job.
Reflowable EPUB requires a lot more preparation. View Anne-Marie Concepcion's videos on Lynda.com to find out all the setup required.
Thanks for that!
We have previously coded a reflowable book to "look" fixed format. Just wasn't mentally prepared to do that for the next book.
I guess the only option would be to bump the font size.
Thanks for the plug, Steve!
Cicho, one of the strengths/limitations of a Fixed Layout Format epub is that users cannot change the size of the type. It makes no difference if it's viewed on a Kindle or iPad or Kobo. The "Aa" button/icon that lets users customize font size, typeface, background color, etc. does not appear when you're reading a Fixed Layout (FXL) epub.
f they could change the size of the type, then the text might reflow, but of course it can't reflow since it's not a reflowable epub. ;-D You can think of a FXL epub like a PDF. All you can do is zoom in or out, you can't change the size of the type alone.
Additionally, as Steve said, Kindles have a different way of presenting flowable and fixed layout ebooks, and the EPUB standard is not used. It would be great if Adobe could add Kindle-specific export formats, but they won't. As a rule, they only export to their own or to industry standard formats, not to vendors' proprietary ones.