kmpdfkit_demo/compdfkit_demo_windows/compdfkit/compdfkit-tools/util/assets/styles/TextBoxStyle.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style x:Key="style.clear" TargetType="{x:Type Button}">
        <Setter Property="BorderThickness" Value="0"></Setter>
        <Setter Property="Background" Value="Transparent"></Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="Button">
                    <ContentPresenter VerticalAlignment="Center" HorizontalAlignment="Center"></ContentPresenter>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>