styleH3 function
Implementation
TextStyle? styleH3(AppModel app, BuildContext context) =>
    StyleRegistry.registry()
        .styleWithApp(app)
        .frontEndStyle()
        .textStyleStyle()
        .styleH3(app, context);TextStyle? styleH3(AppModel app, BuildContext context) =>
    StyleRegistry.registry()
        .styleWithApp(app)
        .frontEndStyle()
        .textStyleStyle()
        .styleH3(app, context);