Header Height; Font-size of Page title; Font-size of Main Menu

Hello I would like to increase the height of the header by approx. 50% including the the fonts which are in it, i.e. page title and menus. When I do several changes for the style, is it possible to insert them all in the custom CSS, meaning one after the other. My wepsite is as follows. http://www.schlaufer.ch/ Sorry but I couldn’t find the answers by myself. I would appreciate your help.