Designing for Kobo
I've just designed an ebook which works well on my Sony PRS T2 and on my iPad with iBooks, and after being converted by calibre works well on my Kindle3 both in old mobi and azw3. I design my ebooks by hand with an HTML editor, and the html files and CSS validate to W3C standards. The ebook validates with ePubCheck and Flightcrew.
But a friend has tested it on her Kobo Touch, and it seems to be an absolute disaster - links don't go to the right page, the font size is too small, and there are several other problems. It's also a disaster using the Kobo app on my iPad2. The friend has tested other ebooks I've designed for me, and found although links didn't work the rest of the ebook worked well.
Can anyone suggest where I might have done wrong? Is there a difference between how Kobo renders ePubs and how Sony renders ePubs?
Are there any ePub designers here who read their ebooks on a Kobo?