It's again not clear on which area you want to reduce/remove the space. Since I believe you want to remove top and bottom space on the header logo. If that is the case than in
theme-folder/qa-styles.css around line #524 find below code
.qa-header {
width: 1000px;
margin: 0 auto;
padding: 75px 0 90px;
}
Now replace padding to reduce the space. Something like below
.qa-header {
width: 1000px;
margin: 0 auto;
padding: 15px 0 60px;
}