Alex, if you look at most ePub, you'll see that's not a good style.
Font sizes, margins all over the place,. Hugh spacing at the top of the page for a new chapter. Line spaces between paragraphs, Too much space between sections. And indents too large if there are any.
All of that is what you find in most ePub eBooks. Make an ePub eBook look good.
Take a look at the non-Sony edition of
For the Win to see what I think is a good style.
https://www.mobileread.com/forums/showthread.php?t=83384
This wills how you what font I prefer, what staling in terms of margins, indents, and paragraph spacing. To me, this is a good format that will work for most people (IMHO).