[Katsunami]

Maybe people know FeedBooks.com. They have a lot of public domain books, that are formatted very nicely.

I've have noticed that, when converting from EPUB to AZW3 for the Paperwhite, the header markup goes awry. Feedbooks uses a huge (and I mean HUGE) chapter number. See Attachment 1.

Not all of FeedBooks EPUB's have this markup, but there are many that do, and they all seem to use the same classnames, at least the ones I've tested. Of course I can't predict what will happen if you use this CSS on a book that does not have this particular markup.

The Kindle Paperwhite / AZW3 doesn't seem to support that correctly. See Attachment 2 to see how it looks.

While this is not unusable by any means, it doesn't look pretty. With some extra CSS, the chapter heading can be fixed, allthough the huge chapter number will be smaller (even though the size is still set at 94px. I haven't investigated this). See attachment 3 to see how it looks. If you want, you could try to keep the huge chapter number, and make the font size even bigger than 94px, but I have not tested this.

Here is the CSS you can use in "Extra CSS" when converting to AZW3, to obtain a layout as is shown in the third attachment. (Note that, if you open this AZW3 in the Calibre viewer, it will look wrong.)

.chapterHeader {
  text-align: left;
  margin-bottom: 50px;
}

.chapterHeader .translation {
  margin-left: -5px;
}
                             
.chapterHeader .count {
  font-size: 94px;
  margin-right: 0px;
  margin-top: 40px;
  margin-bottom: 0px;
}

.text {
  clear: both;
}

Hopefully someone else but me has some use for this

PS: You can also convert to MOBI (old MOBI 6 format), which does not support markup such as this, and the file will look fine. However, I can understand that people may not want to convert to such an old format if they have a new Kindle.