Changing space between header image and menu.

I've left Site Title and Blog Info blank and only used a logo. The space between the logo and where the menu starts is big. I'd like to be able to remove it (or edit it to a smaller one). http://s8.postimg.org/4wvwde8g5/mass.jpg I've tried adding the following to Custom CSS but it does nothing: #header-menu { padding-top: 0; } Can anyone help? Thanks!