diff --git a/.gitmodules b/.gitmodules
index 93c30ae..a16f4b2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "FusionCalculator"]
 	path = FusionCalculator
-	url = https://timerix.ddns.net:3322/Timerix/FusionCalculator.git
+	url = https://timerix.ddns.net/git/Timerix/FusionCalculator.git
diff --git a/README.md b/README.md
index fb093a7..281a220 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ Requirements: git, bash, [dotnet8](https://dotnet.microsoft.com/en-us/download/d
 
 1. ensure that [FusionCalculator](https://github.com/Timerix22/FusionCalculator) submodule is up-to-date.
     ```shell
-    git submodule init && git submodule update
+    it submodule update --init
     ```
 2. Translate FusionCalculator to C#
     ```shell
diff --git a/SharpCalculator.Avalonia/App.axaml b/SharpCalculator.Avalonia/App.axaml
index 070776c..a27e594 100644
--- a/SharpCalculator.Avalonia/App.axaml
+++ b/SharpCalculator.Avalonia/App.axaml
@@ -11,14 +11,14 @@
             <Setter Property="VerticalAlignment" Value="Center"/>
         </Style>
         
-        <Style Selector="Button.cirlce">
-            <Setter Property="Height" Value="60"/>
-            <Setter Property="Width" Value="60"/>
-            <Setter Property="CornerRadius" Value="30"/>
-            <Setter Property="HorizontalAlignment" Value="Center"/>
-            <Setter Property="VerticalAlignment" Value="Center"/>
+        <Style Selector="Button.button">
+            <Setter Property="HorizontalAlignment" Value="Stretch"/>
+            <Setter Property="VerticalAlignment" Value="Stretch"/>
             <Setter Property="HorizontalContentAlignment" Value="Center"/>
             <Setter Property="VerticalContentAlignment" Value="Center"/>
+            <Setter Property="BorderThickness" Value="0"/>
+            <Setter Property="Margin" Value="1"/>
+            <Setter Property="Padding" Value="0"/>
         </Style>
         
         <Style Selector="Button.gray">
diff --git a/SharpCalculator.Avalonia/MainWindow.axaml b/SharpCalculator.Avalonia/MainWindow.axaml
index 1e81b3f..729f869 100644
--- a/SharpCalculator.Avalonia/MainWindow.axaml
+++ b/SharpCalculator.Avalonia/MainWindow.axaml
@@ -5,6 +5,7 @@
     Title="SharpCalculator"
     Icon="avares://SharpCalculator.Avalonia/assets/icon.ico"
     FontFamily="Consolas" FontSize="24"
+    MinWidth="460" MinHeight="570"
     Width="460" Height="570">
 
     <Grid Margin="10">
@@ -14,7 +15,9 @@
                  TextChanged="Input_OnTextChanged"
                  BorderThickness="2"
                  BorderBrush="#AAAAAA"
-                 TextWrapping="Wrap"/>
+                 TextWrapping="Wrap"
+                 ScrollViewer.HorizontalScrollBarVisibility="Disabled"
+                 ScrollViewer.VerticalScrollBarVisibility="Auto"/>
         
         <TextBlock Grid.Row="1" 
                    VerticalAlignment="Center" 
@@ -26,7 +29,9 @@
                  VerticalContentAlignment="Center"
                  IsReadOnly="True"
                  BorderThickness="0"
-                 TextWrapping="NoWrap"/>
+                 TextWrapping="NoWrap"
+                 ScrollViewer.HorizontalScrollBarVisibility="Auto"
+                 ScrollViewer.VerticalScrollBarVisibility="Disabled"/>
         
         <TextBox Name="History" Grid.Row="2"
                  Foreground="Gray"
@@ -34,7 +39,9 @@
                  BorderBrush="Gray"
                  IsReadOnly="True"
                  TextWrapping="NoWrap"
-                 FontSize="18"/>
+                 FontSize="18"
+                 ScrollViewer.HorizontalScrollBarVisibility="Auto"
+                 ScrollViewer.VerticalScrollBarVisibility="Auto"/>
         
         <Grid Grid.Row="3" VerticalAlignment="Bottom"
               MinWidth="440" MaxWidth="440" MinHeight="320" MaxHeight="320">
@@ -43,119 +50,119 @@
             
             <!--  1st row  -->
             
-            <Button Classes="cirlce gray" Grid.Column="0" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="0" Grid.Row="0"
                 Click="ClearButton_OnClick" Content="AC"/>
 
-            <Button Classes="cirlce gray" Grid.Column="1" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="1" Grid.Row="0"
                 Click="MathButton_OnClick" Content="("/>
             
-            <Button Classes="cirlce gray" Grid.Column="2" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="2" Grid.Row="0"
                 Click="MathButton_OnClick" Content=")" />
             
-            <Button Classes="cirlce orange" Grid.Column="3" Grid.Row="0"
+            <Button Classes="button orange" Grid.Column="3" Grid.Row="0"
                 Click="MathButton_OnClick" Content="/"/>
 
-            <Button Classes="cirlce gray" Grid.Column="4" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="4" Grid.Row="0"
                 Click="MathButton_OnClick" Content="1/x"/>
 
-            <Button Classes="cirlce gray" Grid.Column="5" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="5" Grid.Row="0"
                 Click="MathButton_OnClick" Content="sin"/>
 
-            <Button Classes="cirlce gray" Grid.Column="6" Grid.Row="0"
+            <Button Classes="button gray" Grid.Column="6" Grid.Row="0"
                 Click="MathButton_OnClick" Content="asin"/>
 
             <!--  2nd row  -->
 
-            <Button Classes="cirlce" Grid.Column="0" Grid.Row="1"
+            <Button Classes="button" Grid.Column="0" Grid.Row="1"
                 Click="MathButton_OnClick" Content="7"/>
 
-            <Button Classes="cirlce" Grid.Column="1" Grid.Row="1"
+            <Button Classes="button" Grid.Column="1" Grid.Row="1"
                 Click="MathButton_OnClick" Content="8"/>
             
-            <Button Classes="cirlce" Grid.Column="2" Grid.Row="1"
+            <Button Classes="button" Grid.Column="2" Grid.Row="1"
                 Click="MathButton_OnClick" Content="9"/>
             
-            <Button Classes="cirlce orange" Grid.Column="3" Grid.Row="1"
+            <Button Classes="button orange" Grid.Column="3" Grid.Row="1"
                 Click="MathButton_OnClick" Content="*"/>
 
-            <Button Classes="cirlce gray" Grid.Column="4" Grid.Row="1"
+            <Button Classes="button gray" Grid.Column="4" Grid.Row="1"
                 Click="MathButton_OnClick" Content="^"/>
 
-            <Button Classes="cirlce gray" Grid.Column="5" Grid.Row="1"
+            <Button Classes="button gray" Grid.Column="5" Grid.Row="1"
                 Click="MathButton_OnClick" Content="cos"/>
 
-            <Button Classes="cirlce gray" Grid.Column="6" Grid.Row="1"
+            <Button Classes="button gray" Grid.Column="6" Grid.Row="1"
                 Click="MathButton_OnClick" Content="acos"/>
 
             <!--  3th row  -->
 
-            <Button Classes="cirlce" Grid.Column="0" Grid.Row="2"
+            <Button Classes="button" Grid.Column="0" Grid.Row="2"
                 Click="MathButton_OnClick" Content="4"/>
 
-            <Button Classes="cirlce" Grid.Column="1" Grid.Row="2"
+            <Button Classes="button" Grid.Column="1" Grid.Row="2"
                 Click="MathButton_OnClick" Content="5"/>
 
-            <Button Classes="cirlce" Grid.Column="2" Grid.Row="2"
+            <Button Classes="button" Grid.Column="2" Grid.Row="2"
                 Click="MathButton_OnClick" Content="6"/>
 
-            <Button Classes="cirlce orange" Grid.Column="3" Grid.Row="2"
+            <Button Classes="button orange" Grid.Column="3" Grid.Row="2"
                 Click="MathButton_OnClick" Content="-"/>
 
-            <Button Classes="cirlce gray" Grid.Column="4" Grid.Row="2"
+            <Button Classes="button gray" Grid.Column="4" Grid.Row="2"
                 FontSize="22"
                 Click="MathButton_OnClick" Content="10^x"/>
 
-            <Button Classes="cirlce gray" Grid.Column="5" Grid.Row="2"
+            <Button Classes="button gray" Grid.Column="5" Grid.Row="2"
                 Click="MathButton_OnClick" Content="tg"/>
 
-            <Button Classes="cirlce gray" Grid.Column="6" Grid.Row="2"
+            <Button Classes="button gray" Grid.Column="6" Grid.Row="2"
                 Click="MathButton_OnClick" Content="atg"/>
 
             <!--  4th row  -->
 
-            <Button Classes="cirlce" Grid.Column="0" Grid.Row="3"
+            <Button Classes="button" Grid.Column="0" Grid.Row="3"
                 Click="MathButton_OnClick" Content="1"/>
 
-            <Button Classes="cirlce" Grid.Column="1" Grid.Row="3"
+            <Button Classes="button" Grid.Column="1" Grid.Row="3"
                 Click="MathButton_OnClick" Content="2"/>
 
-            <Button Classes="cirlce" Grid.Column="2" Grid.Row="3"
+            <Button Classes="button" Grid.Column="2" Grid.Row="3"
                 Click="MathButton_OnClick" Content="3"/>
 
-            <Button Classes="cirlce orange" Grid.Column="3" Grid.Row="3"
+            <Button Classes="button orange" Grid.Column="3" Grid.Row="3"
                 Click="MathButton_OnClick" Content="+"/>
 
-            <Button Classes="cirlce gray" Grid.Column="4" Grid.Row="3"
+            <Button Classes="button gray" Grid.Column="4" Grid.Row="3"
                 Click="MathButton_OnClick" Content="e"/>
 
-            <Button Classes="cirlce gray" Grid.Column="5" Grid.Row="3"
+            <Button Classes="button gray" Grid.Column="5" Grid.Row="3"
                 Click="MathButton_OnClick" Content="ctg"/>
 
-            <Button Classes="cirlce gray" Grid.Column="6" Grid.Row="3"
+            <Button Classes="button gray" Grid.Column="6" Grid.Row="3"
                 Click="MathButton_OnClick" Content="actg"/>
 
             <!--  5th row  -->
 
-            <Button Classes="cirlce" Grid.Column="0" Grid.Row="4"
+            <Button Classes="button" Grid.Column="0" Grid.Row="4"
                 Click="MathButton_OnClick" Content="0"/>
 
-            <Button Classes="cirlce" Grid.Column="1" Grid.Row="4"
+            <Button Classes="button" Grid.Column="1" Grid.Row="4"
                 Click="MathButton_OnClick" Content="."/>
 
-            <Button Classes="cirlce" Grid.Column="2" Grid.Row="4"
+            <Button Classes="button" Grid.Column="2" Grid.Row="4"
                 Click="MathButton_OnClick" Content="%"/>
 
-            <Button Classes="cirlce orange" Grid.Column="3" Grid.Row="4"
+            <Button Classes="button orange" Grid.Column="3" Grid.Row="4"
                 Click="ResultButton_OnClick" Content="="/>
 
-            <Button Classes="cirlce gray" Grid.Column="4" Grid.Row="4"
+            <Button Classes="button gray" Grid.Column="4" Grid.Row="4"
                 Click="MathButton_OnClick" Content="π"/>
 
-            <Button Classes="cirlce gray" Grid.Column="5" Grid.Row="4"
+            <Button Classes="button gray" Grid.Column="5" Grid.Row="4"
                 FontSize="22"
                 Click="MathButton_OnClick" Content="rand"/>
 
-            <Button Classes="cirlce gray" Grid.Column="6" Grid.Row="4" 
+            <Button Classes="button gray" Grid.Column="6" Grid.Row="4" 
                 Click="MathButton_OnClick" Content="ln"/>
             </Grid>
     </Grid>
diff --git a/SharpCalculator.Avalonia/MainWindow.axaml.cs b/SharpCalculator.Avalonia/MainWindow.axaml.cs
index ab0d0e5..a54535b 100644
--- a/SharpCalculator.Avalonia/MainWindow.axaml.cs
+++ b/SharpCalculator.Avalonia/MainWindow.axaml.cs
@@ -1,3 +1,4 @@
+using Avalonia.Input;
 using FusionCalculator;
 
 namespace SharpCalculator.Avalonia;
@@ -9,6 +10,31 @@ public partial class MainWindow : Window
     public MainWindow()
     {
         InitializeComponent();
+        // https://github.com/AvaloniaUI/Avalonia/discussions/12179
+        KeyDownEvent.AddClassHandler<TopLevel>(GlobalOnKeyDown, handledEventsToo: true);
+    }
+
+    private void GlobalOnKeyDown(object? sender, KeyEventArgs e)
+    {
+        switch (e.Key)
+        {
+            case Key.Enter:
+                CalculateResult();
+                break;
+            case Key.Delete:
+                Clear();
+                break;
+        }
+    }
+
+    private void CalculateResult()
+    {
+        if(Input.Text == null || Output.Text == null || Output.Text.StartsWith("Error"))
+            return;
+        string expression = Input.Text;
+        string result = Output.Text;
+        AppendToHistory($"{expression}={result}");
+        Input.Text = result;
     }
     
     private void AppendToHistory(string line) //function of appending expression to the history list
@@ -24,6 +50,23 @@ public partial class MainWindow : Window
             .Replace("  ", " ");
     }
 
+    private void Clear()
+    {
+        Input.Clear();
+        Output.Clear();
+    }
+    
+    private void ResultButton_OnClick(object? sender, RoutedEventArgs e)
+    {
+        CalculateResult();
+    }
+    
+    
+    private void ClearButton_OnClick(object? sender, RoutedEventArgs e)
+    {
+        Clear();
+    }
+
     private void MathButton_OnClick(object? sender, RoutedEventArgs e)
     {
         if (sender is not Button button)
@@ -48,30 +91,6 @@ public partial class MainWindow : Window
             _ => buttonText
         };
     }
-    
-    private void ClearButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        Input.Text = "";
-        Output.Text = "";
-    }
-
-    private void UndoButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        // delete last digit
-        // if (!string.IsNullOrEmpty(Input.Text)) 
-        //     Input.Text = Input.Text.Remove(Input.Text.Length - 1);
-        Input.Undo();
-    }
-    
-    private void ResultButton_OnClick(object? sender, RoutedEventArgs e)
-    {
-        if(Input.Text == null || Output.Text == null || Output.Text.StartsWith("Error"))
-            return;
-        string expression = Input.Text;
-        string result = Output.Text;
-        AppendToHistory($"{expression}={result}");
-        Input.Text = result;
-    }
 
     private void Input_OnTextChanged(object? sender, TextChangedEventArgs e)
     {
diff --git a/SharpCalculator.Avalonia/SharpCalculator.Avalonia.csproj b/SharpCalculator.Avalonia/SharpCalculator.Avalonia.csproj
index 5190cb9..4c987de 100644
--- a/SharpCalculator.Avalonia/SharpCalculator.Avalonia.csproj
+++ b/SharpCalculator.Avalonia/SharpCalculator.Avalonia.csproj
@@ -11,10 +11,10 @@
     </PropertyGroup>
     
     <ItemGroup>
-        <PackageReference Include="Avalonia" Version="11.0.6" />
-        <PackageReference Include="Avalonia.Desktop" Version="11.0.6" />
-        <PackageReference Include="Avalonia.Themes.Simple" Version="11.0.6" />
-        <PackageReference Condition="'$(Configuration)' == 'Debug'" Include="Avalonia.Diagnostics" Version="11.0.6" />
+        <PackageReference Include="Avalonia" Version="11.3.10" />
+        <PackageReference Include="Avalonia.Desktop" Version="11.3.10" />
+        <PackageReference Include="Avalonia.Themes.Simple" Version="11.3.10" />
+        <PackageReference Condition="'$(Configuration)' == 'Debug'" Include="Avalonia.Diagnostics" Version="11.3.10" />
     </ItemGroup>
     
     <ItemGroup>
diff --git a/SharpCalculator.Tests/SharpCalculator.Tests.csproj b/SharpCalculator.Tests/SharpCalculator.Tests.csproj
index e656b1d..f06b46a 100644
--- a/SharpCalculator.Tests/SharpCalculator.Tests.csproj
+++ b/SharpCalculator.Tests/SharpCalculator.Tests.csproj
@@ -9,13 +9,13 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-        <PackageReference Include="xunit" Version="2.6.4" />
-        <PackageReference Include="xunit.runner.visualstudio" Version="2.5.6">
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+        <PackageReference Include="xunit" Version="2.9.3" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>
-        <PackageReference Include="coverlet.collector" Version="6.0.0">
+        <PackageReference Include="coverlet.collector" Version="6.0.4">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>