Thanks for responding and offering help. I'm not having much luck with this theme...I made the changes you suggested above to style.css in the child theme but nothing happened. I thought this might be because when I copied style.css to the child theme I renamed it stylechild.css, so I had style.css and stylechild.css in the folder.
So, I created just one style.css in the child theme. Since then, I cannot see Modularity Child as a theme in WordPress, but I can see it when I log in to FTP. I'm not quite sure what has happened. When I create a new Modularity Child theme, it says it already exists, but I just can't see it listed in WP! I've tried deleting both child and parent theme, and re installing, but it still doesn't recognise the child theme.
I have since made your suggested changes directly in the parent theme (I know you are not supposed to do this, but I wanted to test), but it didn't make the changes to the font size/black box.
I'm going a little crazy here, what am I doing wrong???!!!
I had started building my site in twenty eleven but couldn't move the nav bar with page links up in line with the logo and to the right(as per the links in Modularity Lite). Could you please offer me some advice, should I just stay with twenty eleven and hope someone can advise how to move the page links (I did post on the forum but noone responded) OR try and get Modularity lite to work?
Sorry to have gone on a little bit but I'm really struggling here to get my site going.
Thank you so much in advance Hfort.