Enter custom CSS

Hi I am trying to make a few changes to my Catch Responsible Free theme:- Change font of Site Title and center it Change font to ROBOTO for all of the site Change font and colour of Menu text and center it. (firstly I tried to remove the search box from the menu bar but when I went into the Navigation I only got two options Select or Menu - no option to disable search box). Remove the black background in the menu bar I have read the forums and tried to add the codes to make the changes in the Enter Custom CSS box, then hit save and publish and nothing happens! Can you tell me what I am doing wrong. I am working on an ipad. Thank you