change header spacings

im trying to get rid of the spacing between my header image and social icons. also when im on full scrteen theres alot of space on the sides and id like to remove it. also is there a way to change the colours of the boxes of the page titles. id like to have dirrent colours please. apologies for so much info and thanks for your time my site address is http://www.thegastronomiccamper.com/wp-admin