junction/src/Junction.App/App.axaml

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:Junction.App"
             xmlns:conv="clr-namespace:Junction.App.Converters"
             x:Class="Junction.App.App"
             RequestedThemeVariant="Default">
    <!-- RequestedThemeVariant="Default" = follow the OS light/dark preference. -->

    <Application.Resources>
        <ResourceDictionary>
            <!-- Per-variant palette. Fluent supplies the base chrome; these are Junction's
                 accent + surface + status tokens, adapted for Light and Dark. -->
            <ResourceDictionary.ThemeDictionaries>
                <ResourceDictionary x:Key="Light">
                    <SolidColorBrush x:Key="AccentBrush" Color="#2563EB" />
                    <SolidColorBrush x:Key="AccentHoverBrush" Color="#1D4FD7" />
                    <SolidColorBrush x:Key="AppBackgroundBrush" Color="#F4F6F9" />
                    <SolidColorBrush x:Key="CardBackgroundBrush" Color="#FFFFFF" />
                    <SolidColorBrush x:Key="CardBorderBrush" Color="#E2E6EC" />
                    <SolidColorBrush x:Key="HeaderForegroundBrush" Color="#161A1F" />
                    <SolidColorBrush x:Key="SubtleForegroundBrush" Color="#697586" />
                    <SolidColorBrush x:Key="DangerBrush" Color="#C62828" />
                    <SolidColorBrush x:Key="OnAccentBrush" Color="#FFFFFF" />
                </ResourceDictionary>
                <ResourceDictionary x:Key="Dark">
                    <SolidColorBrush x:Key="AccentBrush" Color="#4C8DF6" />
                    <SolidColorBrush x:Key="AccentHoverBrush" Color="#6BA1F8" />
                    <SolidColorBrush x:Key="AppBackgroundBrush" Color="#1B1E23" />
                    <SolidColorBrush x:Key="CardBackgroundBrush" Color="#24282E" />
                    <SolidColorBrush x:Key="CardBorderBrush" Color="#3A3F46" />
                    <SolidColorBrush x:Key="HeaderForegroundBrush" Color="#F2F4F7" />
                    <SolidColorBrush x:Key="SubtleForegroundBrush" Color="#9AA3AF" />
                    <SolidColorBrush x:Key="DangerBrush" Color="#EF5350" />
                    <SolidColorBrush x:Key="OnAccentBrush" Color="#FFFFFF" />
                </ResourceDictionary>
            </ResourceDictionary.ThemeDictionaries>

            <!-- Spacing scale (variant-invariant). -->
            <Thickness x:Key="PageMargin">20</Thickness>

            <!-- Variant-invariant converters. -->
            <conv:StatusKindToBrushConverter x:Key="StatusKindToBrush" />
            <conv:ProtocolIdToIconConverter x:Key="ProtocolIdToIcon" />
        </ResourceDictionary>
    </Application.Resources>

    <Application.DataTemplates>
        <local:ViewLocator />
    </Application.DataTemplates>

    <Application.Styles>
        <FluentTheme />
        <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml" />

        <!-- Inter (bundled via WithInterFont) as the shell default for a consistent, crisp face. -->
        <Style Selector="Window">
            <Setter Property="FontFamily" Value="avares://Avalonia.Fonts.Inter/Assets#Inter" />
            <Setter Property="Background" Value="{DynamicResource AppBackgroundBrush}" />
        </Style>

        <!-- Reusable text roles. -->
        <Style Selector="TextBlock.h1">
            <Setter Property="FontSize" Value="22" />
            <Setter Property="FontWeight" Value="SemiBold" />
            <Setter Property="Foreground" Value="{DynamicResource HeaderForegroundBrush}" />
        </Style>
        <Style Selector="TextBlock.h2">
            <Setter Property="FontSize" Value="16" />
            <Setter Property="FontWeight" Value="SemiBold" />
            <Setter Property="Foreground" Value="{DynamicResource HeaderForegroundBrush}" />
        </Style>
        <Style Selector="TextBlock.subtle">
            <Setter Property="Foreground" Value="{DynamicResource SubtleForegroundBrush}" />
        </Style>
        <Style Selector="TextBlock.fieldLabel">
            <Setter Property="FontWeight" Value="SemiBold" />
            <Setter Property="Foreground" Value="{DynamicResource SubtleForegroundBrush}" />
        </Style>

        <!-- Card / section container. -->
        <Style Selector="Border.card">
            <Setter Property="Background" Value="{DynamicResource CardBackgroundBrush}" />
            <Setter Property="BorderBrush" Value="{DynamicResource CardBorderBrush}" />
            <Setter Property="BorderThickness" Value="1" />
            <Setter Property="CornerRadius" Value="6" />
            <Setter Property="Padding" Value="16" />
        </Style>

        <!-- Primary (accent) button. -->
        <Style Selector="Button.accent">
            <Setter Property="Background" Value="{DynamicResource AccentBrush}" />
            <Setter Property="Foreground" Value="{DynamicResource OnAccentBrush}" />
            <Setter Property="FontWeight" Value="SemiBold" />
        </Style>
        <Style Selector="Button.accent:pointerover /template/ ContentPresenter">
            <Setter Property="Background" Value="{DynamicResource AccentHoverBrush}" />
            <Setter Property="Foreground" Value="{DynamicResource OnAccentBrush}" />
        </Style>

        <!-- Destructive button. -->
        <Style Selector="Button.danger">
            <Setter Property="Background" Value="{DynamicResource DangerBrush}" />
            <Setter Property="Foreground" Value="#FFFFFF" />
            <Setter Property="FontWeight" Value="SemiBold" />
        </Style>

        <!-- Protocol glyph. -->
        <Style Selector="PathIcon.protocol">
            <Setter Property="Width" Value="16" />
            <Setter Property="Height" Value="16" />
            <Setter Property="Foreground" Value="{DynamicResource AccentBrush}" />
        </Style>
    </Application.Styles>
</Application>