Remove empty space on top of pages

Hi, I have the same problem – too much white space above the header image. I tried some custom CSS, but nothing seems to work. Please advise. [Aside: I love this theme. I switched from a paid theme to this and now have it for 2 sites. Thank you. Simple, clean.]

Site: http://freeagenteconomics.com

Custom CSS added as below.

//
#header-img {
padding-top: 0;
margin-top: 0;
}

.header-wrap {
margin: 0;
}

#site-title {
margin: 0;
line-height: 0;
}

#site-description {
margin: 0;
line-height: 0;
}
//