Themes/MaterialDesign3.Window.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:wpf="clr-namespace:MaterialDesignThemes.Wpf">
  <Style x:Key="MaterialDesignWindow" TargetType="Window">
    <Setter Property="Background" Value="{DynamicResource MaterialDesign.Brush.Background}" />
    <Setter Property="FontFamily" Value="{wpf:NotoFont}" />
    <Setter Property="TextElement.FontSize" Value="14" />
    <Setter Property="TextElement.FontWeight" Value="Regular" />
    <Setter Property="TextElement.Foreground" Value="{DynamicResource MaterialDesign.Brush.Foreground}" />
    <Setter Property="TextOptions.TextFormattingMode" Value="Ideal" />
    <Setter Property="TextOptions.TextRenderingMode" Value="Auto" />
  </Style>
</ResourceDictionary>