Why is Header bigger than Title, when to use each?

Question

Header styles are bigger than title styles in the Window type ramp, which is opposite of common use in PDFs, Microsoft Word, and print. Why are these styles seemingly swapped, and in what scenarios did the designers intend us to use each?

Clarification: I am not asking how to "fix" it. As a developer, I need to know the original intent of the styles so I use them properly as-is.

Answer 1

It is by designed in UWP. But you could change these styles easily to adjust your thoughts.

For example, you could find the HeaderTextBlockStyle in generic.xaml(let your mouse poniter hover the HeaderTextBlockStyle in your xaml code and press F12), and copy the code of HeaderTextBlockStyle into your Page.Resource or Application.Resources. Then, change the FontSize property in a Setter statement or other target properties to fit your requirements.