Center header image across top of whole page

Before I upgraded to Pro, I had the header image centered across the top of the whole page. I do not want any social media icons, so I made all the values in those blank, but of course the socialmedia class still exists and takes up the right 35% of the header.

Using custom CSS I tried making the width of the socialmedia class 0% but I still can’t seem to get my header image to center up on the page. Best I can do is put a 180 px left margin on the logo, but that defeats the nice responsive layout that you have.

I do not want to edit your CSS directly, in order to keep from having to re-do it when the theme is updated. So I am using a custom CSS plugin, kind of like adjusting the position of an antique chest of drawers by using a sledge hammer.

http://www.rfwoodworking.com/wp/

Tried this css in a custom css plugin:

.site-header {
width: 100%;
text-align: center;
}

.header-image {
margin: 24px auto 10px auto;
}
.themonic-logo img {
margin-left: 180px;
text-align: center;
}