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">
    <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="u:OverlayDialogHost.IsModalStatusScope" Value="True" />
        <Setter Property="IsMinimizeButtonVisible" Value="{OnPlatform {x:True},macOS={x:False}}" />
        <Setter Property="IsRestoreButtonVisible" Value="{OnPlatform {x:True},macOS={x:False}}" />
        <Setter Property="IsCloseButtonVisible" Value="{OnPlatform {x:True},macOS={x:False}}"/>
        <Setter Property="SystemDecorations">
            <OnPlatform>
                <On Options="Default">
                    <SystemDecorations>Full</SystemDecorations>
                </On>
                <On Options="Linux">
                    <SystemDecorations>None</SystemDecorations>
                </On>
            </OnPlatform>
        </Setter>
        <Setter Property="Template">
            <ControlTemplate TargetType="u:UrsaWindow">
                <Panel>
                    <Border Name="PART_TransparencyFallback" IsHitTestVisible="False" />
                    <Border
                        Background="{TemplateBinding Background}"
                        BackgroundSizing="InnerBorderEdge"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        IsHitTestVisible="False" />
                    <Panel Margin="{TemplateBinding WindowDecorationMargin}" Background="Transparent" />
                    <VisualLayerManager Padding="{TemplateBinding OffScreenMargin, Mode=OneWay}">
                        <VisualLayerManager.ChromeOverlayLayer>
                            <Panel Margin="{Binding $parent[u:UrsaWindow].OffScreenMargin}">
                                <u:TitleBar
                                    IsTitleBarHitTestVisible="{Binding $parent[u:UrsaWindow].(u:TitleBar.IsTitleBarHitTestVisible)}"
                                    Margin="{Binding $parent[u:UrsaWindow].TitleBarMargin}"
                                    Content="{Binding $parent[u:UrsaWindow].TitleBarContent}"
                                    IsTitleVisible="{Binding $parent[u:UrsaWindow].IsTitleBarVisible}"
                                    LeftContent="{Binding $parent[u:UrsaWindow].LeftContent}"
                                    RightContent="{Binding $parent[u:UrsaWindow].RightContent}" />
                                <VisualLayerManager>
                                    <Panel>
                                        <u:OverlayDialogHost 
                                            Name="{x:Static u:UrsaWindow.PART_DialogHost}" 
                                            IsModalStatusReporter="True" 
                                            IsTopLevel="True" />
                                        <u:WindowResizer
                                            HorizontalAlignment="Stretch"
                                            VerticalAlignment="Stretch"
                                            IsVisible="{Binding $parent[u:UrsaWindow].IsManagedResizerVisible}" />
                                    </Panel>
                                </VisualLayerManager>
                            </Panel>
                        </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>
                        <u:WindowThumb
                            Background="{TemplateBinding Background}"
                            IsHitTestVisible="{TemplateBinding IsTitleBarHitTestVisible}" />
                        <Grid HorizontalAlignment="Stretch" ColumnDefinitions="Auto, *, Auto, Auto">
                            <ContentPresenter
                                Grid.Column="0"
                                Content="{TemplateBinding LeftContent}"
                                IsVisible="{TemplateBinding IsTitleVisible}" />
                            <ContentPresenter
                                Grid.Column="1"
                                Content="{TemplateBinding Content}"
                                IsVisible="{TemplateBinding IsTitleVisible}" />
                            <ContentPresenter
                                Grid.Column="2"
                                Content="{TemplateBinding RightContent}"
                                IsVisible="{TemplateBinding IsTitleVisible}" />
                            <u:CaptionButtons
                                Name="{x:Static u:TitleBar.PART_CaptionButtons}"
                                Grid.Column="3"
                                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="Foreground" Value="{DynamicResource CaptionButtonForeground}" />
        <Setter Property="Template">
            <ControlTemplate TargetType="u:CaptionButtons">
                <StackPanel Orientation="Horizontal">
                    <Button Name="PART_FullScreenButton" Theme="{StaticResource CaptionButton}">
                        <PathIcon
                            Name="PART_FullScreenButtonIcon"
                            Theme="{StaticResource InnerPathIcon}"
                            Data="{StaticResource WindowExpandGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button Name="PART_MinimizeButton" Theme="{StaticResource CaptionButton}">
                        <PathIcon
                            Name="PART_MinimizeButtonIcon"
                            Theme="{StaticResource InnerPathIcon}"
                            Data="{StaticResource WindowMinimizeGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button Name="PART_RestoreButton" Theme="{StaticResource CaptionButton}">
                        <PathIcon
                            Name="PART_RestoreButtonIcon"
                            Theme="{StaticResource InnerPathIcon}"
                            Data="{StaticResource WindowMaximizeGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                    <Button Name="PART_CloseButton" Theme="{StaticResource CaptionButton}">
                        <PathIcon
                            Name="PART_CloseButtonIcon"
                            Theme="{StaticResource InnerPathIcon}"
                            Data="{StaticResource WindowCloseIconGlyph}"
                            Foreground="{Binding $parent[Button].Foreground}" />
                    </Button>
                </StackPanel>
            </ControlTemplate>
        </Setter>

        <Style Selector="^ /template/ Button#PART_CloseButton:pointerover">
            <Setter Property="Foreground" Value="White" />
            <Setter Property="Background" Value="{DynamicResource CaptionButtonClosePointeroverBackground}" />
        </Style>
        <Style Selector="^ /template/ Button#PART_CloseButton:pressed">
            <Setter Property="Foreground" Value="White" />
            <Setter Property="Background" Value="{DynamicResource CaptionButtonClosePressedBackground}" />
        </Style>

        <Style Selector="^:maximized /template/ PathIcon#PART_RestoreButtonIcon">
            <Setter Property="Data" Value="{StaticResource WindowRestoreGlyph}" />
        </Style>
        <Style Selector="^:fullscreen /template/ PathIcon#PART_FullScreenButtonIcon">
            <Setter Property="Data" Value="{StaticResource WindowCollapseGlyph}" />
        </Style>
    </ControlTheme>
</ResourceDictionary>