Masonry CSS

Hi, I'd like to add some gutter to a 2-column category layout which uses masonry.
I just can't find where it is happening.
I tried to apply a flex model with 49% column width, which works until the end of the rendering, then masonry comes along and overwrites it.
Masonry has a selector for "gutter", but I can't seem to find out how to apply it.

hello can you provide a like to see css problem ?

I'm working on it here
hear.wildezeiten.de/news
The certificate isn't working, you have to add an exception.

When it renders, you could see that it puts the items in two columns, with the space justified in the middle. Flex is doing that thru the selector "justify-content: space-between;"
Then towards the end of the rendering, masonry applies the absolute postion to the item containers and messes it up.

Where is the masonry applied? I can't find it.

Masonry has an option to apply gutter
masonry.desandro.com/options.html#gutter

I just can't find out how to apply it.

hello did you check in template option > feature > style
you have the padding and the marging of the box and item box

I don't have that, this is the template info.
Would you be bothered just to answer any of my questions and tell me where this masonry stuff happens, and where the css for masonry could be found?