Stefania,
Just to make sure we’re seeing the same thing, this is what it looks like in Firefox for me:
http://d.pr/i/sXsl
If you need more space in the header there are a couple of options for you.
1) We released an update to the theme since the version you’re using that changes how the logo is structured. It looks the same, but should make the spacing easier.
2) The other option is to edit this spot in the style.css file:
header {
position: relative;
z-index: 1002;
height: 30px;
margin-bottom: 112px;
overflow: visible;
background-color: transparent;
background-color: rgba(0, 0, 0, 0.84);
}
The margin-bottom: 112px; actually sets the height of the logo area. You can increase it to get more space for your logo.
If you have any trouble, let me know,
Bill