Hi there,
thats correct – each OS will have its own system font – so the style will be different.
The only font-family styles listed in the GP Stylesheets will be for the System Stack eg.
font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
Which is what defines the System Fonts for the various browser types and relevant fallbacks.
And in addition to that is the font-family for the GP Icons