as we see from screenshot, this is not because of transparent menu but because you have too many menu items and they do not fit into one line. That`s why it goes to second.
You have 2 ways to fix it:
1. Move some of the items into submenus.
2. Use below css to decrease padding between current items:
#Top_bar .menu > li > a span:not(.description) { padding: 0 10px; }
Each custom css should be always added in Theme options > Layout > Custom CSS & JS > Custom CSS section because from this place is safely stored in database and you won`t lose it after theme update.
Comments
as we see from screenshot, this is not because of transparent menu but because you have too many menu items and they do not fit into one line. That`s why it goes to second.
You have 2 ways to fix it:
1. Move some of the items into submenus.
2. Use below css to decrease padding between current items:
#Top_bar .menu > li > a span:not(.description) { padding: 0 10px; }