can't change homepage color in the navigation menu

hi im a noob to wordpress.
i’m using the twentytwelve theme and i have created a child theme to do some style editing. i’ve managed to change the background, font color and hover color of all the pages in the menu except for the home page.
for some reason the main-nav code doesn’t effect it.
i’ve tried looking for other places to change the code in but i couldn’t find any.

here is a link to the website:

thanks for the help!