Originally Posted by Frank's
Not possible for me, because I would need just a simple tool to highlight the text when I study the book. Has to be a quick and easy thing.
If CSS or inline styles and code editing are not possible for you, then Sigil's just not going to be the tool that quickly and easily does what you want. I don't really know of any WYSIWYG html editors capable of quickly/easily creating highlighted text (not to say there aren't any, of course) to tell the truth. That's always been more a function of the reading
app/device rather than a creation-time feature.