Space between header and page content on Goran theme

I would like to reduce the wasted space (padding?) below my header image and the page content on the Goran theme. I have spent hours trying to research the correct custom CSS to add and have just figured out that it’s not the body/content area that needs to be changed, it’s the actual header itself. The link to the dev site is:

https://www.kdesignhouse.co.za/clients/keystone/about/

I have reduced the slider images’ height but this doesn’t help – it just leaves the default red background showing (which I’m also unable to remove).

Any help would be MUCH appreciated!