TextCell Font-Size

I need to change the textCell fontSize and use css file:

#cellaListView{

    font-size:larger; 
}

in xaml i have:

    <ListView x:Name="listaDati"  StyleId="listView" >
        <ListView.ItemTemplate>
            <DataTemplate>
                <TextCell TextColor="Red"  Text="{Binding}" StyleId="cellaListView" >

                </TextCell>

            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

WHY the font size does not CHANGE??

THANKS