Navbar Filled Style

The kitchen sink example has a color theme switcher that changes navbars to “filled” style. All the other theme controls on this demo add classes to the html element that obvious to see and utilize. I see no obvious classes added for this filled navbar style and i cannot seem to figure out how its changing the navbars to the filled style. I searched the documentation on navbars and see nothing on the navbar documentation about the filled style (unless im missing it). What is this control changing in the app to get the filled navbar style?

Create custom class witch styles or change CSS variables in your CSS file

In Kitchen Sink demo page with colors you will see a CSS variables you need to add to your custom CSS file