MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="BorderThickness.MainPage">

    <ScrollView>
        <VerticalStackLayout
            Padding="30,0"
            Spacing="25">
            <Image
                Source="dotnet_bot.png"
                HeightRequest="185"
                Aspect="AspectFit"
                SemanticProperties.Description="dot net bot in a race car number eight" />

            <VerticalStackLayout Grid.Column="1"
                                 Spacing="0">
                <Border StrokeThickness="0"
                        Margin="5,5,5,0"
                        Padding="0">
                    <Border.StrokeShape>
                        <RoundRectangle CornerRadius="3,3,0,0" />
                    </Border.StrokeShape>
                    <Label BackgroundColor="{StaticResource Secondary}"
                           HeightRequest="30"
                           HorizontalOptions="Fill" />
                </Border>
                <Border StrokeThickness="0"
                        Margin="5,0,5,5"
                        Padding="0">
                    <Border.StrokeShape>
                        <RoundRectangle CornerRadius="0,0,0,0" />
                    </Border.StrokeShape>
                    <Label BackgroundColor="{StaticResource Tertiary}"
                           HeightRequest="30"
                           HorizontalOptions="Fill" />

                </Border>
            </VerticalStackLayout>

            <Button
                x:Name="CounterBtn"
                Text="Click me" 
                SemanticProperties.Hint="Counts the number of times you click"
                Clicked="OnCounterClicked"
                HorizontalOptions="Fill" />
        </VerticalStackLayout>
    </ScrollView>

</ContentPage>