Baseline: WPF/Avalonia/Cli/Core + plans (BROWSER_FEATURES_PLAN v2, MOBILE_PLAN v1)

VideoDownloader.Avalonia/MainWindow.axaml

@@ -0,0 +1,63 @@
+<Window xmlns="https://github.com/avaloniaui"
+        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"
+        x:CompileBindings="False"
+        mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="520"
+        x:Class="VideoDownloader.Avalonia.MainWindow"
+        Title="VideoDownloader (Avalonia · 크로스플랫폼 셸)"
+        Width="640" Height="520"
+        WindowStartupLocation="CenterScreen">
+
+    <!-- DataContext 는 MainWindow 생성자에서 코드비하인드로 설정(MainViewModel). -->
+
+    <Border Background="#1B1C24" Padding="24">
+        <Grid RowDefinitions="Auto,Auto,Auto,Auto,Auto,*">
+
+            <!-- 헤더 -->
+            <StackPanel Grid.Row="0" Margin="0,0,0,16">
+                <TextBlock Text="VideoDownloader" FontSize="22" FontWeight="SemiBold" Foreground="#E6E6EC"/>
+                <TextBlock Text="Avalonia 크로스플랫폼 셸 — Core 엔진 재사용 (HLS · DASH · yt-dlp 소셜 · 직링크)"
+                           FontSize="12" Foreground="#8A8B95" Margin="0,4,0,0"/>
+            </StackPanel>
+
+            <!-- URL 입력 -->
+            <TextBox Grid.Row="1" x:Name="UrlBox"
+                     Text="{Binding Url, UpdateSourceTrigger=PropertyChanged}"
+                     PlaceholderText="영상 URL 붙여넣기 (YouTube/Instagram/X · m3u8 · mpd · mp4)"
+                     Background="#26272F" Foreground="#E6E6EC"
+                     BorderBrush="#3A3B45" BorderThickness="1" Padding="10,8" CornerRadius="8"/>
+
+            <!-- 버튼 -->
+            <StackPanel Grid.Row="2" Orientation="Horizontal" Margin="0,12,0,12" Spacing="8">
+                <Button Content="받기" Command="{Binding DownloadCommand}"
+                        Background="#5B8DEF" Foreground="White" Padding="24,8" CornerRadius="8" FontWeight="SemiBold"/>
+                <Button Content="취소" Command="{Binding CancelCommand}"
+                        Background="#3A3B45" Foreground="#E6E6EC" Padding="18,8" CornerRadius="8"/>
+            </StackPanel>
+
+            <!-- 진행률 -->
+            <ProgressBar Grid.Row="3" Value="{Binding Progress}" Maximum="100"
+                         MinHeight="6" CornerRadius="3" Foreground="#5B8DEF" Background="#26272F" Margin="0,0,0,8"/>
+
+            <!-- 상태/결과 -->
+            <StackPanel Grid.Row="4" Margin="0,0,0,12">
+                <TextBlock Text="{Binding Status}" Foreground="#B9BAC4" FontSize="13"/>
+                <TextBlock Text="{Binding Result}" Foreground="#7FD1A0" FontSize="13" TextWrapping="Wrap" Margin="0,6,0,0"/>
+            </StackPanel>
+
+            <!-- 로그 -->
+            <Border Grid.Row="5" Background="#202127" CornerRadius="8" Padding="12">
+                <ScrollViewer>
+                    <ItemsControl ItemsSource="{Binding Log}">
+                        <ItemsControl.ItemTemplate>
+                            <DataTemplate>
+                                <TextBlock Text="{Binding}" Foreground="#8A8B95" FontSize="11" Margin="0,2"/>
+                            </DataTemplate>
+                        </ItemsControl.ItemTemplate>
+                    </ItemsControl>
+                </ScrollViewer>
+            </Border>
+        </Grid>
+    </Border>
+</Window>