csharp/mdict/MainWindow.xaml

<Window x:Class="mdict.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:mdict"
        xmlns:views="clr-namespace:mdict.Views"
        mc:Ignorable="d"
        Title="MDict" Height="600" Width="900"
        WindowStartupLocation="CenterScreen">
    
    <Window.Resources>
        <Style x:Key="NavRadioButtonStyle" TargetType="RadioButton">
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="Foreground" Value="#666"/>
            <Setter Property="FontSize" Value="14"/>
            <Setter Property="Padding" Value="15,12"/>
            <Setter Property="Cursor" Value="Hand"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="RadioButton">
                        <Border x:Name="Border" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}" CornerRadius="8" Margin="5,2">
                            <Grid>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto"/>
                                    <ColumnDefinition Width="*"/>
                                </Grid.ColumnDefinitions>
                                <TextBlock x:Name="Icon" Text="{TemplateBinding Tag}" FontFamily="Segoe MDL2 Assets" FontSize="18" VerticalAlignment="Center" HorizontalAlignment="Center" Width="24"/>
                                <ContentPresenter Grid.Column="1" VerticalAlignment="Center" Margin="12,0,0,0"/>
                            </Grid>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter TargetName="Border" Property="Background" Value="#E8E8E8"/>
                                <Setter Property="Foreground" Value="#333"/>
                            </Trigger>
                            <Trigger Property="IsChecked" Value="True">
                                <Setter TargetName="Border" Property="Background" Value="#E3F2FD"/>
                                <Setter Property="Foreground" Value="#1976D2"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <Grid Background="White">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="220"/> <!-- Sidebar -->
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>

        <!-- Sidebar -->
        <Border Grid.Column="0" Background="#F8F9FA" BorderBrush="#EEE" BorderThickness="0,0,1,0">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto"/> <!-- Header -->
                    <RowDefinition Height="*"/>    <!-- Nav Items -->
                    <RowDefinition Height="Auto"/> <!-- Bottom -->
                </Grid.RowDefinitions>

                <!-- Header -->
                <StackPanel Grid.Row="0" Margin="20,30,20,30">
                    <TextBlock Text="MDict" FontSize="24" FontWeight="Bold" Foreground="#333"/>
                    <TextBlock Text="Dictionary" FontSize="12" Foreground="#888" Margin="2,0,0,0"/>
                </StackPanel>

                <!-- Navigation -->
                <StackPanel Grid.Row="1" Margin="10,0">
                    <RadioButton Content="Search" Tag="&#xE721;" GroupName="Nav" IsChecked="True" Style="{StaticResource NavRadioButtonStyle}" Click="Nav_Click" CommandParameter="Search"/>
                    <RadioButton Content="Library" Tag="&#xE8F1;" GroupName="Nav" Style="{StaticResource NavRadioButtonStyle}" Click="Nav_Click" CommandParameter="Library"/>
                    <RadioButton Content="History" Tag="&#xE81C;" GroupName="Nav" Style="{StaticResource NavRadioButtonStyle}" Click="Nav_Click" CommandParameter="History"/>
                    <RadioButton Content="Favorites" Tag="&#xEB51;" GroupName="Nav" Style="{StaticResource NavRadioButtonStyle}" Click="Nav_Click" CommandParameter="Favorites"/>
                    <RadioButton Content="Settings" Tag="&#xE713;" GroupName="Nav" Style="{StaticResource NavRadioButtonStyle}" Click="Nav_Click" CommandParameter="Settings"/>
                </StackPanel>
                
                <!-- Footer/Version -->
                <TextBlock Grid.Row="2" Text="v1.0.0" Foreground="#CCC" HorizontalAlignment="Center" Margin="20" FontSize="10"/>
            </Grid>
        </Border>

        <!-- Main Content -->
        <ContentControl x:Name="MainContent" Grid.Column="1" Margin="0"/>
    </Grid>
</Window>