MainWindow.xaml

<Window x:Class="TicTacToe.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        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"
        xmlns:local="clr-namespace:TicTacToe"
        mc:Ignorable="d"
        Title="Tic Tac Toe" Height="450" Width="800"
        FontFamily="Segoe UI Light"
        Background="{StaticResource BackgroundColor}">
    <Viewbox>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="auto"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>

            <StackPanel x:Name="TurnPanel"
                    Orientation="Horizontal"
                    HorizontalAlignment="Center">
                <TextBlock FontSize="54"
                       Text="Player:"/>
                <Image x:Name="PlayerImage"
                   Source="Assets/X15.png"
                   Height="75"/>
            </StackPanel>

            <Canvas x:Name="GameCanvas"
                Grid.Row="1"
                Width="300"
                Height="300"
                Margin="30">
                <UniformGrid x:Name="GameGrid"
                         Width="300"
                         Height="300"
                         Rows="3"
                         Columns="3"
                         MouseDown="GameGrid_Click">
                    <UniformGrid.Background>
                        <ImageBrush ImageSource="Assets/Grid.png"/>
                    </UniformGrid.Background>
                </UniformGrid>
                <Line x:Name="Line"
                  Stroke="{StaticResource LineColor}"
                  StrokeThickness="10"
                  StrokeStartLineCap="Round"
                  StrokeEndLineCap="Round"
                  Visibility="Hidden"/>
            </Canvas>

            <Grid x:Name="EndScreen"
              Grid.RowSpan="2"
              Background="{StaticResource BackgroundColor}"
              Visibility="Hidden">
                <StackPanel Orientation="Vertical"
                        VerticalAlignment="Center">
                    <StackPanel Orientation="Horizontal"
                            HorizontalAlignment="Center">
                        <TextBlock x:Name="ResultText"
                               FontSize="54"
                               Text="Winner: "
                               Margin="0,0,0,15">

                        </TextBlock>
                        <Image x:Name="WinnerImage"
                           Height="75">

                        </Image>
                    </StackPanel>
                    <Button Content="Play Again"
                    Background="{StaticResource ButtonColor}"
                    FontSize="34"
                    Width="200"
                    Margin="0,20,0,0"
                    Padding="0,0,0,5"
                    BorderBrush="Black"
                    Click="Button_Click"/>
                </StackPanel>

            </Grid>
        </Grid>

    </Viewbox>
</Window>