Hamburger Menu Font Size wont change

Hi Community

I recently got my hamburger menu working great, but I was wondering if anyone knows how to reduce the size of the font on my menu as I find it too big. I have tried the site styles and font change and size options but it changes only the font, not the size. I need to reduce the size to 0.9 size. 

Any tips would be great, thank you!

You can use this code to Website > Website Tools > Custom CSS

div.container.header-menu-nav-item * {
	font-size: 10px !important;
}