Ursa.Avalonia/src/Ursa.Themes.Semi/Controls/UrsaWindow.axaml

<ResourceDictionary
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:u="https://irihi.tech/ursa">
    <!--  Add Resources Here  -->
    <ControlTheme x:Key="{x:Type u:UrsaWindow}" TargetType="u:UrsaWindow">
        <Setter Property="Background" Value="{DynamicResource WindowDefaultBackground}" />
        <Setter Property="TransparencyBackgroundFallback" Value="{DynamicResource WindowDefaultBackground}" />
        <Setter Property="Foreground" Value="{DynamicResource WindowDefaultForeground}" />
        <Setter Property="FontSize" Value="{DynamicResource DefaultFontSize}" />
        <Setter Property="FontFamily" Value="{DynamicResource DefaultFontFamily}" />
        <Setter Property="ExtendClientAreaTitleBarHeightHint" Value="-1" />
        <Setter Property="ExtendClientAreaToDecorationsHint" Value="True" />
        <Setter Property="SystemDecorations" Value="Full" />
        <Setter Property="Template">
            <ControlTemplate TargetType="u:UrsaWindow">
                <Panel>
                    <Border Name="PART_TransparencyFallback" IsHitTestVisible="False" />
                    <Border Background="{TemplateBinding Background}" IsHitTestVisible="False" />
                    <Panel Margin="{TemplateBinding WindowDecorationMargin}" Background="Transparent" />
                    <VisualLayerManager>
                        <VisualLayerManager.ChromeOverlayLayer>
                            <u:TitleBar
                                Content="{Binding $parent[u:UrsaWindow].TitleBarContent}"
                                Margin="{Binding $parent[u:UrsaWindow].TitleBarMargin}"
                                LeftContent="{Binding $parent[u:UrsaWindow].LeftContent}"
                                RightContent="{Binding $parent[u:UrsaWindow].RightContent}" />
                            <u:OverlayDialogHost/>
                        </VisualLayerManager.ChromeOverlayLayer>
                        <Panel>
                            <ContentPresenter
                                Name="PART_ContentPresenter"
                                Margin="{TemplateBinding Padding}"
                                HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                                VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                                Content="{TemplateBinding Content}"
                                ContentTemplate="{TemplateBinding ContentTemplate}" />
                        </Panel>
                    </VisualLayerManager>
                </Panel>
            </ControlTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="{x:Type u:TitleBar}" TargetType="u:TitleBar">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="VerticalAlignment" Value="Top" />
        <Setter Property="HorizontalAlignment" Value="Stretch" />
        <Setter Property="Template">
            <ControlTemplate TargetType="u:TitleBar">
                <Panel Background="Transparent">
                    <Panel>
                        <Border
                            Name="PART_Background"
                            Background="{TemplateBinding Background}"
                            IsHitTestVisible="True" />
                        <Grid ColumnDefinitions="Auto, *, Auto, Auto" HorizontalAlignment="Stretch">
                            <ContentPresenter
                                Grid.Column="0"
                                VerticalAlignment="Center"
                                Content="{TemplateBinding LeftContent}" />
                            <ContentPresenter
                                Grid.Column="1"
                                VerticalAlignment="Center"
                                Content="{TemplateBinding Content}" />
                            <ContentPresenter
                                Grid.Column="2"
                                VerticalAlignment="Center"
                                Content="{TemplateBinding RightContent}" />
                            <u:CaptionButtons
                                x:Name="PART_CaptionButtons"
                                Grid.Column="3"
                                Margin="8 0"
                                HorizontalAlignment="Right"
                                VerticalAlignment="Top"
                                DockPanel.Dock="Right"
                                Foreground="{TemplateBinding Foreground}" />
                        </Grid>
                    </Panel>
                </Panel>
            </ControlTemplate>
        </Setter>
    </ControlTheme>

    <ControlTheme x:Key="{x:Type u:CaptionButtons}" TargetType="u:CaptionButtons">
        <Setter Property="Template">
            <ControlTemplate TargetType="u:CaptionButtons">
                <StackPanel
                    VerticalAlignment="Stretch"
                    Orientation="Horizontal"
                    Spacing="2"
                    TextElement.FontSize="10">
                    <Button x:Name="PART_FullScreenButton" Theme="{DynamicResource CaptionButton}">
                        <PathIcon
                            Name="PART_FullScreenButtonIcon"
                            Width="12"
                            Height="12"
                            Data="{DynamicResource WindowExpandGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button x:Name="PART_MinimizeButton" Theme="{DynamicResource CaptionButton}">
                        <PathIcon
                            Width="12"
                            Height="12"
                            Data="{DynamicResource WindowMinimizeGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button x:Name="PART_RestoreButton" Theme="{DynamicResource CaptionButton}" >
                        <PathIcon
                            Name="PART_RestoreButtonIcon"
                            Width="12"
                            Height="12"
                            Data="{DynamicResource WindowMaximizeGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button
                        x:Name="PART_CloseButton"
                        Background="{DynamicResource CaptionButtonClosePointeroverBackground}"
                        BorderBrush="{DynamicResource CaptionButtonClosePressedBackground}"
                        Theme="{DynamicResource CaptionButton}">
                        <Button.Styles>
                            <Style Selector="Button:pointerover">
                                <Setter Property="Foreground" Value="White" />
                            </Style>
                            <Style Selector="Button:pressed">
                                <Setter Property="Foreground" Value="White" />
                            </Style>
                        </Button.Styles>
                        <PathIcon
                            Width="12"
                            Height="12"
                            Data="{DynamicResource WindowCloseIconGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                </StackPanel>
            </ControlTemplate>
        </Setter>
    </ControlTheme>
</ResourceDictionary>