Inner Header

Hi there – I am designing a website (http://www.youjackbstard.co.uk/)

I have a logo on there but I want the padding around the logo (top and bottom) to disappear – I have googled and tried some different options on css code but when I put it into the custom css section nothing seems to change? I dont want to change the size of the logo banner itself if I can avoid it

Can anyone help? Sorry if this is a stupid question