If you take a look around line 635 in your css file, you’ll see the code for the #header –
`#header {
color: #aaa;
margin: 0 auto;
overflow: hidden;
padding: 5px 0;
padding: 0.3125rem 0;
max-width: 1152px;
}`
You can adjust the padding (top and bottom) and it will add more space. This theme uses “rem” so most modern browsers will probably reference that first. You’ll need to adjust both of the padding properties if you want to continue using the rem…..if not, you could remove the rem and just use the regular padding by adjusting the 5px to 10px or whatever you want. Let me know if you need assistance in figuring out how to convert the px to rem. I hope I didn’t make this sound too confusing