diff --git a/ColorTools/ColorControlPanel.xaml b/ColorTools/ColorControlPanel.xaml
index 00f7d97..1911b62 100644
--- a/ColorTools/ColorControlPanel.xaml
+++ b/ColorTools/ColorControlPanel.xaml
@@ -5,7 +5,7 @@
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
              xmlns:local="clr-namespace:ColorTools"
              mc:Ignorable="d" 
-             d:DesignHeight="160" d:DesignWidth="400">
+             d:DesignHeight="160" d:DesignWidth="400" FontFamily="Segoe UI">
 
     <!-- ******* RESOURCES ******* -->
     <UserControl.Resources>
@@ -349,7 +349,7 @@
                     </LinearGradientBrush>
                 </Rectangle.Fill>
             </Rectangle>
-            <Ellipse x:Name="thumbSV" Height="14" Stroke="#FFB9B9B9" Width="14" Fill="#FF38879F" Canvas.Left="97.731" Canvas.Top="71.578"/>
+            <Ellipse x:Name="thumbSV" Height="14" Stroke="White" Width="14" Fill="#FF38879F" Canvas.Left="97.731" Canvas.Top="71.578"/>
         </Canvas>
         <Rectangle x:Name="SVbounds" Stroke="Black" Margin="0" d:LayoutOverrides="LeftPosition, RightPosition, TopPosition, BottomPosition"/>
 
@@ -369,11 +369,11 @@
 
         <DockPanel x:Name="RGBAdock" Grid.Column="2" Margin="5,0,0,0">
             <DockPanel x:Name="dockRed" Height="25" LastChildFill="true" Margin="0,0,0,5" DockPanel.Dock="Top">
-                <Label x:Name="labelR" DockPanel.Dock="Left" Content="R" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2" FontFamily="Cambria Math"/>
+                <Label x:Name="labelR" DockPanel.Dock="Left" Content="R" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2"/>
                 <TextBox x:Name="txtRvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" 
                          Background="{Binding TextBoxBackground, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:ColorControlPanel}}}" 
                          Foreground="{Binding TextForeground, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:ColorControlPanel}}}"
-                         HorizontalContentAlignment="Center" FontFamily="Cambria Math" VerticalContentAlignment="Bottom" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38" BorderBrush="{x:Null}"/>
+                         HorizontalContentAlignment="Center" VerticalContentAlignment="Bottom" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38" BorderBrush="{x:Null}" PreviewTextInput="TextBoxPreviewTextInput"/>
                 <Slider x:Name="sliderRed" Style="{StaticResource SliderColorComponent}" BorderBrush="{x:Null}" 
                         Maximum="255" SmallChange="1" Foreground="#FF570000" VerticalAlignment="Center" 
                         Margin="0,0,5,0" LargeChange="15" Value="25" Focusable="False" IsMoveToPointEnabled ="True">
@@ -386,8 +386,8 @@
                 </Slider>
             </DockPanel>
             <DockPanel x:Name="dockGreen" Height="25" LastChildFill="true" Margin="0,0,0,5" DockPanel.Dock="Top">
-                <Label x:Name="labelG" DockPanel.Dock="Left" Content="G" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2" FontFamily="Cambria Math"/>
-                <TextBox x:Name="txtGvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue, Mode=TwoWay}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" FontFamily="Cambria Math" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38"/>
+                <Label x:Name="labelG" DockPanel.Dock="Left" Content="G" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2"/>
+                <TextBox x:Name="txtGvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue, Mode=TwoWay}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38" PreviewTextInput="TextBoxPreviewTextInput"/>
                 <Slider x:Name="sliderGreen" Style="{StaticResource SliderColorComponent}" BorderBrush="{x:Null}" 
                         Value="25" Maximum="255" SmallChange="1" Foreground="#FF003D00" 
                         VerticalAlignment="Center" Margin="0,0,5,0" LargeChange="15" Focusable="False" IsMoveToPointEnabled ="True">
@@ -400,8 +400,8 @@
                 </Slider>
             </DockPanel>
             <DockPanel x:Name="dockBlue" Height="25" LastChildFill="true" Margin="0,0,0,5" DockPanel.Dock="Top">
-                <Label x:Name="labelB" DockPanel.Dock="Left" Content="B" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue, Mode=TwoWay}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2" FontFamily="Cambria Math"/>
-                <TextBox x:Name="txtBvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" FontFamily="Cambria Math" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38"/>
+                <Label x:Name="labelB" DockPanel.Dock="Left" Content="B" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue, Mode=TwoWay}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2"/>
+                <TextBox x:Name="txtBvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38" PreviewTextInput="TextBoxPreviewTextInput"/>
                 <Slider x:Name="sliderBlue" Style="{StaticResource SliderColorComponent}" BorderBrush="{x:Null}" 
                         Value="25" Maximum="255" SmallChange="1" Foreground="#FF000056" VerticalAlignment="Center"
                         Margin="0,0,5,0" LargeChange="15" Focusable="False" IsMoveToPointEnabled ="True">
@@ -414,8 +414,8 @@
                 </Slider>
             </DockPanel>
             <DockPanel x:Name="dockAlpha" Height="25" LastChildFill="true" Margin="0,0,0,5" DockPanel.Dock="Top" Visibility="{Binding DockAlphaVisibility, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:ColorControlPanel}}}">
-                <Label x:Name="labelA" DockPanel.Dock="Left" Content="A" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2" FontFamily="Cambria Math"/>
-                <TextBox x:Name="txtAvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" FontFamily="Cambria Math" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38"/>
+                <Label x:Name="labelA" DockPanel.Dock="Left" Content="A" ScrollViewer.VerticalScrollBarVisibility="Disabled" Foreground="{Binding Foreground, ElementName=txtRvalue}" Width="25" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" FontSize="16" Padding="2"/>
+                <TextBox x:Name="txtAvalue" DockPanel.Dock="Right" TextWrapping="Wrap" Text="255" Background="{Binding Background, ElementName=txtRvalue}" Foreground="{Binding Foreground, ElementName=txtRvalue}" HorizontalContentAlignment="Center" VerticalContentAlignment="Bottom" BorderBrush="{x:Null}" Margin="0" VerticalAlignment="Center" Padding="0,1,0,0" FontSize="16" Height="25" Width="38" PreviewTextInput="TextBoxPreviewTextInput"/>
                 <Slider x:Name="sliderAlpha" Style="{DynamicResource SliderAlphaComponent}" BorderBrush="{x:Null}" 
                         Value="25" Maximum="255" SmallChange="1" Foreground="#FF979797" 
                         VerticalAlignment="Center" Margin="0,0,5,0" LargeChange="15" Focusable="False" IsMoveToPointEnabled ="True">
@@ -429,7 +429,7 @@
             </DockPanel>
             <DockPanel x:Name="dockSelectedColor" DockPanel.Dock="Bottom" VerticalAlignment="Bottom">
                 <TextBox x:Name="txtColorCode" TextWrapping="Wrap" Text="#AAAAAAAA"
-                             DockPanel.Dock="Right" VerticalAlignment="Bottom" Background="{Binding Background, ElementName=txtRvalue, Mode=TwoWay}" Foreground="{Binding Foreground, ElementName=txtRvalue}" FontSize="14" FontFamily="Lucida Console" BorderBrush="{x:Null}" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Width="95" Height="27" Padding="0"/>
+                             DockPanel.Dock="Right" VerticalAlignment="Bottom" Background="{Binding Background, ElementName=txtRvalue, Mode=TwoWay}" Foreground="{Binding Foreground, ElementName=txtRvalue}" FontSize="14" BorderBrush="{x:Null}" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Width="95" Height="27" Padding="0" PreviewTextInput="ColorCode_PreviewTextInput"/>
                 <Grid Height="25" Background="{StaticResource CheckerBackground}" DockPanel.Dock="Right" Margin="10,0,2,0" VerticalAlignment="Center" ClipToBounds="True">
                     <Grid.ColumnDefinitions>
                         <ColumnDefinition/>
@@ -443,5 +443,5 @@
 
         </DockPanel>
     </Grid>
-    
+
 </UserControl>
diff --git a/ColorTools/ColorControlPanel.xaml.cs b/ColorTools/ColorControlPanel.xaml.cs
index 7fd6bdf..586f161 100644
--- a/ColorTools/ColorControlPanel.xaml.cs
+++ b/ColorTools/ColorControlPanel.xaml.cs
@@ -15,6 +15,7 @@
 using System.Windows.Media.Imaging;
 using System.Windows.Navigation;
 using System.Windows.Shapes;
+using System.Text.RegularExpressions;
 
 namespace ColorTools
 {
@@ -834,6 +835,18 @@ private static void IniColorChanged(DependencyObject d, DependencyPropertyChange
                                                             new FrameworkPropertyMetadata(new SolidColorBrush(Color.FromRgb(85, 85, 85)),
                                                                                           new PropertyChangedCallback(SelectedColorChanged)));
 
+        private void TextBoxPreviewTextInput(object sender, TextCompositionEventArgs e)
+        {
+            Regex regex = new Regex("[^0-9]+");
+            e.Handled = regex.IsMatch(e.Text);
+        }
+
+        private void ColorCode_PreviewTextInput(object sender, TextCompositionEventArgs e)
+        {
+            Regex regex = new Regex("^([A-Fa-f0-9]{2}){8,9}$");
+            e.Handled = regex.IsMatch(e.Text);
+        }
+
         public SolidColorBrush SelectedColorBrush
         {
             get { return (SolidColorBrush)GetValue(SelectedColorBrushProperty); }
diff --git a/TEST_ColorPanel/TEST_ColorPanel.csproj b/TEST_ColorPanel/TEST_ColorPanel.csproj
index 94a7e79..500ee06 100644
--- a/TEST_ColorPanel/TEST_ColorPanel.csproj
+++ b/TEST_ColorPanel/TEST_ColorPanel.csproj
@@ -37,7 +37,7 @@
   <ItemGroup>
     <Reference Include="ColorTools, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\ColorTools\bin\Release\ColorTools.dll</HintPath>
+      <HintPath>..\ColorTools\bin\Debug\ColorTools.dll</HintPath>
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Data" />