[Theme: MINIMATICA] Remove the gray line below my posts

Hi, hi!

I’m making a website using the minimatica theme and first of all I wanna say – I love this teme, it looks so nice! But I there is one thing I can’t quite figure out. I have gotten rid of the “sidebar” and “leave comments” at my posts but there is always this small gray line under each post that I can’t get rid of.

There is another gray line above the menu at the bottom of the site and I like that line. But this other line (below each post) I’d like very much to get rid of. Does anyone know how to do that?