UWP -更改返回按钮颜色，而不更改最小化/关闭按钮颜色

<Grid x:Name="TitleBar" Background="{ThemeResource SystemControlBackgroundChromeMediumBrush}">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>
    <Button x:Name="BackButton" Grid.Column="0" Click="BackButton_Click">
        <SymbolIcon Symbol="Back"/>
    </Button>
    <TextBlock x:Name="Title" Grid.Column="1" Text="My App"/>
    <Button x:Name="MinimizeButton" Grid.Column="2" Click="MinimizeButton_Click">
        <SymbolIcon Symbol="Remove"/>
    </Button>
    <Button x:Name="CloseButton" Grid.Column="2" Click="CloseButton_Click">
        <SymbolIcon Symbol="Cancel"/>
    </Button>
</Grid>

private void BackButton_Click(object sender, RoutedEventArgs e)
{
    // 处理返回按钮点击事件
}

private void MinimizeButton_Click(object sender, RoutedEventArgs e)
{
    // 处理最小化按钮点击事件
}

private void CloseButton_Click(object sender, RoutedEventArgs e)
{
    // 处理关闭按钮点击事件
}

<Page
    x:Class="MyApp.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MyApp"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">
    
    <Grid>
        <local:CustomTitleBar/>
        <!-- 其他页面内容 -->
    </Grid>
</Page>