<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="0.35*"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>

    <Grid Grid.Row="0">
        <TextBlock Text="Заголовок страницы" HorizontalAlignment="Center" VerticalAlignment="Top" FontSize="35" Padding="0 10 0 25" FontFamily="Calibri Bold" Name="Title"/>
        <TextBlock Text="Подзаголовок" HorizontalAlignment="Center" VerticalAlignment="Top" FontSize="25" Padding="0 50 0 0" FontFamily="Calibri" Name="SubTitle"/>
    </Grid>

    <Grid Grid.Row="1">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions>
            <RowDefinition Height="0.5*"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <StackPanel Grid.Row="0" Orientation="Horizontal" Grid.ColumnSpan="4" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="25">
                <TextBlock Text="Варианты: " FontSize="18" Name="Options"/>
            <ComboBox SelectedIndex="1" Padding="2" FontSize="18" SelectionChanged="ComboBox_SelectionChanged" Name="dm">
                <ComboBoxItem>2</ComboBoxItem>
                <ComboBoxItem>3</ComboBoxItem>
                <ComboBoxItem>4</ComboBoxItem>
                <ComboBoxItem>5</ComboBoxItem>
            </ComboBox>
        </StackPanel>
</Grid>