Menu Size Not Changing with Custom CSS

Hello,
I am trying to reduce the size of the top menus however custom CSS does not seem to be working. I used code found on this forum for a different template. When I save nothing changes. Can you please advise?

Thanks!

 

Paste this code in Custom CSS
Appearance > Theme Option > Styling Option > Custom CSS

Code:

#menu .ddsmoothmenu li a{
font-size:12px!important;
}