[Yaretzki]

Hi,
I'm very new to koreader and from the beginning I have some issues with it.

I've found a lot of useful guidelines here and I hope I can find with your help solutions.

All my books are epubs and I used to convert them into mobi for kindle pw.
Now I have kobo glo hd and uploaded some of my ePub books. In nickel books look fine , using nickels features I'm able to adjust all I need for my readings.
Due to some reasons I prefer koreader and here are my problems:
1. I would like to keep book embedded style and be able to change font. But I found it is not possible to change font.
2. So I switched off book embedded style in order to change fonts.
3. After that I have problem with my paragraphs style. In my books after every paragraph there is empty line (added while converting in calibre). After switching off book style these empty lines are removed, headers/chapters are not on central position, style is removed

How to force koreader to keep style and be able to change fonts?
Or
How use book style when embedded style option is switched off?

I see there option to change render style and possibility to select from listed. I looked at all these files ePub.css or cr3.css but nothing works for me.
I found some information at post #2352 here but still with no success.
All I want (at the moment) is just to change font, (but for it I have to switch off book style, and this removes empty lines after paragraph) so I want them still visible... Like rest of book style... Somehow...

Thanks in advance for any help and support!
Y.