I’ve been trying to figure out how to do this all afternoon and while looking at the same question on some other themes, figured it out!
If you go into the Stylesheet (style.css) and head down to #3 Header you can alter the padding which is default 70. I changed mine to 220 for the result I wanted. I honestly wasn’t expecting the padding to be related to the header height lol
3. Header
* ----------------------------------------------------------------------------
*
* Styles for the theme header
*/
.header {
padding: 70px 0;
}