I am reading epubs using ebook-viewer 3.48 (I'm on macOS High Sierra so can't run Calibre 4 or 5).
When looking at the TOC sidebar, some books show the current chapter I'm reading highlighted in bold/italic. Other books do not show the current chapter highlighted.
I know this must have something to do with how my epubs are constructed or formatted, but I can't figure out what it is.
Thank you
ETA: Nevermind. I figured it out. It was the filepath using
../Text/chapter01.xhtml instead of
chapter01.xhtml