Microsoft NET’s WPF (Windows Presentation Foundation) is a GUI-creation solution kind of similar to HTML + CSS.
IMO, it is much more versatile than HTML, but still easy to use (and to create readable GUI code).
Defining layout is as easy as this:
<DockPanel>
<Label Content="Dock Panel Layout Demo"
FontSize="15" FontWeight="Bold" Background="LightBlue"
Foreground="Blue" DockPanel.Dock="Top"/>
<Label Content="Footer" FontSize="15" FontWeight="Bold"
Background="LightGray"
DockPanel.Dock="Bottom" />
<Label Content="Left Pane" FontSize="15" FontWeight="Bold"
Width="125" Background="Firebrick"
DockPanel.Dock="Left"/>
<Label Content="Content Pane" FontSize="15" FontWeight="Bold"
Width="255"
Background="Beige"/>
<Label Content="Right Pane" FontSize="15" FontWeight="Bold"
Width="125" Background="Khaki"
DockPanel.Dock="Right"/>
</DockPanel>
And styles:
<Window.Resources>
<Style x:Key="myStyle" TargetType="Button">
<Setter Property="Background" Value="Orange" />
<Setter Property="FontStyle" Value="Italic" />
<Setter Property="Padding" Value="8,4" />
<Setter Property="Margin" Value="4" />
</Style>
</Window.Resources>