Make Space Between Menus Transparent

On my website at I have two navigation bars separated by a 20px space. The 20px space was achieved by custom CSS:

/* Navigation Space Between Menus */
.secondary-navigation.grid-container.grid-parent {
padding-top: 20px;}

I have no idea if that was the right way to make the space between them, but I would like it to be transparent instead of blue. Can you tell me please how to do this.

Thank you.