Flatiron - Space between projects

Site URL: https://www.inessilvadesign.com

Hey guys,

I am trying to add a space between projects on the front page of my website. I am using this CSS code: 

#grid .item {
    padding: 20px !important;
    box-sizing: border-box;
}

The problem is that when I hover the images the hovering color doesn't match the image... How can I fix this?

Thank You!