I defined an OnPlatform style of type x:Double in my main Styles.xaml which I want to use for defining different font sizes per platform. The problem is when I want to call the resource via the specified x:Key the font size of the label does not change.

My Styles.xaml file:

<ResourceDictionary 
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:controls="clr-namespace:ClientApp.Source.Controls"
    xmlns:views="clr-namespace:ClientApp.Source.Views">


    <OnPlatform x:Key="TinyFontSize" x:TypeArguments="x:Double">
        <On Platform="Default" Value="12" />
    </OnPlatform>
...

In a ContentPage I created following label:

...
 <Label FontSize="{StaticResource TinyFontSize}" Text="Test" WidthRequest="200"/>
...

but the font size of the label does not change to size 12 only when I replace {StaticResource TinyFontSize} with a numeric value.

When I create following resource in the Styles.xaml file:

   <x:Double x:Key="SmallFontSize">13</x:Double>

it would work fine but then I can not change the value depending on the operating system from the main Styles.xaml

I found a example on github in the eShop repository:
https://github.com/dotnet/eShop/blob/main/src/ClientApp/Views/CheckoutView.xaml

But even when I checkout this project and run the ClientApp it does not work…

Using:
net8.0
Microsoft.Maui.Controls (8.0.21)