Add White Text overlay & spacing to recent blog on front page

Hello!

I would like to have the grid style blog posts on my front page, but instead of having the black title written below the image, I would like it to be the style of the full width recent posts with the white lettering on top of the image. How can I do this?

Also, how can I add spacing between the full width recent blog posts?

My URL is http://www.ahumanexistance.com if you can check it out to see what I am talking about.

Thank you!