Update shell's mini size and color.

fis/App.axaml

@@ -2,6 +2,6 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="fis.App">
     <Application.Styles>
-        <FluentTheme Mode="Dark"/>
+        <FluentTheme Mode="Light"/>
     </Application.Styles>
 </Application>

fis/MainWindow.axaml

@@ -14,6 +14,6 @@
           <RowDefinition Height="*"/>
       </Grid.RowDefinitions>
       <Border BorderBrush="Black" BorderThickness="1,1,1,0" Grid.Row="0" VerticalAlignment="Top" Background="Black" IsHitTestVisible="False"/>
-      <Border BorderBrush="Black" BorderThickness="1,0,1,1" Grid.Row="1" x:Name="BrowserBorder"/>
+      <Border BorderBrush="White" BorderThickness="1,0,1,1" Grid.Row="1" x:Name="BrowserBorder"/>
   </Grid>
 </Window>

fis/MainWindow.axaml.cs

@@ -21,7 +21,8 @@ namespace fis
         {
             WindowStartupLocation = WindowStartupLocation.CenterScreen;
             WindowState = WindowState.Maximized;
-
+            MinWidth = 1280;
+            MinHeight = 720;
             InitializeComponent();
 #if DEBUG
             this.AttachDevTools();