Lighter background color for code folding block/area


The code folding feature divides the text into foldable blocks. Now when I click on a line, the background color of the line changes. Is there a way to change not only the color of the single line, but of the whole folding block (without folding it, of course)?
Folding blocks can be nested, I want to change only the lowest level, usually just a couple of lines around the selcted line.

I am using the Atom Dark Theme, so the background is dark grey, the selected line is light grey; maybe the block background color could be something in between.

I think WinEdt once had such a feature, not sure though.

PS: Sorry if I use the wrong words, I have never done any theming at all…