As times and technology have changed the need for web based applications has really faded away. Trying to cram all the native device functionality into the browser using the shims and hacks for all these years has been very frustrating to say the least. I’m moving into native desktop and mobile application development.
For Windows Desktop I’m using the Win UI 3 application development environment to develop the modern responsive applications for Windows 10 and Beyond.
Here is the XAML for a responsive grid for WinUI 3 Application Development

<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="10*"/>
<RowDefinition Height="87*"/>
<RowDefinition Height="3*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="2*"/>
</Grid.ColumnDefinitions>
<!-- Top Row -->
<Border Grid.Row="0" Grid.ColumnSpan="2" Background="LightBlue">
<TextBlock Text="Top Row" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
<!-- Left Column of Second Row -->
<Border Grid.Row="1" Grid.Column="0" Background="SkyBlue">
<TextBlock Text="Second Row Left Column" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
<!-- Right Column of Second Row -->
<Border Grid.Row="1" Grid.Column="1" Background="DodgerBlue">
<TextBlock Text="Second Row Right Column" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
<!-- Bottom Row -->
<Border Grid.Row="2" Grid.ColumnSpan="2" Background="SteelBlue">
<TextBlock Text="Bottom Row" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</Grid>