Space above header image

Hello, I have my logo incorporated in an image an inserted as a Header Featured Image. It show up, but I still have some space above it. Tried to get rid of it by inserting some custom CSS but it does not seem to work see: rondomverliesenrouw.nl Also if I hover over the HOME section of the menu's (top and Bottom) I see a little cap between the different menu items. Is there a way to make this all look the same? Thanks in advance, Bob