Menu Height

I started a child theme as I needed to re-organize the layout.

Works nice except I can't correct the height of the Main menu.

I can adjust
layout - primary navigation - menu item eight, to 30 px and it is saved.

However, on going to a new page, it defaults to 60px.

I tried to add the following additional css code, but no effect.

.main-navigation ul ul {
height: 30px;
}