Logo and Logo Area

I just started on my website. Newbie. 🙂

I want to adjust the logo area, to 1140px x 100px.
Looking at the code view on Safari, it appears the logo area currently is 1140px x 131px.

I am using Directory Theme with child-theme AfterAte.

I wanted my logo full width or at least 600px wide.
My logo is 1180px x 100px.

I searched the forum and found this code to make my logo full width.

#core_logo {
width: 100%;
}

Now my logo has space under it.
1) I would like to reduce the logo “space” height to 100px.
2) Also, my 1180 image is not filling up the smaller 1140 space.?? Why would that be?
My logo is pushed to the left and there is a bit of space to the right.

Thanks!