How to change a cell background of a DataGrid in a style based on the current element of a collection

I have a collection of objects that have a collection of other objects in the following way:

public class Elemento
{
    public string Nombre {get; set;}

    public ObservableCollection<OtroObjeto> Lista {get; set;}
}

In WPF, I link a collection of "Element" in a DataGrid in this way:

<DataGrid ItemsSource={Binding ColeccionElementos}>
    <DataGridTextColumn Header="Nombre" Binding="{Binding Nombre}"/>
    <DataGridTextColumn Header="Dia 1" Binding="{Binding Lista[0].Dia}"/>
    <DataGridTextColumn Header="Dia 2" Binding="{Binding Lista[1].Dia}"/>
    <DataGridTextColumn Header="Dia 3" Binding="{Binding Lista[2].Dia}"/>
</DataGrid>

So far, everything works fine.

If I want to change the background of a cell based on the day value of the element corresponding to the column, I can do it that way, and it works well (I use a converter that transforms the data into a color).

<DataGrid ItemsSource={Binding ColeccionElementos}>
    <DataGridTextColumn Header="Nombre" Binding="{Binding Nombre}">

    <DataGridTextColumn Header="Dia 1" Binding="{Binding Lista[0].Dia}">
        <DataGridTextColumn.CellStyle>
            <Style TargetType="DataGridCell">
                <Setter Property="Background" Value="{Binding Lista[0].Dato, Converter={StaticResource MiConvertidor}}"/>
            </Style>
        </DataGridTextColumn.CellStyle>
    </DataGridTextColumn>
    ...
</DataGrid>

The problem arises when I want to translate the style of the cell to a ResourceDictionary. I put it like that, but I color the entire row based on the data of the first day.

<Style x:Key="EstiloCelda" TargetType="DataGridCell">
    <Setter Property="Background" Value="{Binding Lista/Dato, Converter={StaticResource MiConvertidor}}"/>
</Style>

I have also tried Lista[/].Dato and many other combinations and the result is, or the same, or does not recognize the Binding.

How can I refer to the current item in the List from the ResourceDictionary?

Thanks and best regards.

[EDITED]

Here is a valid example

public class Trabajador
{
    public string Nombre { get; set; }

    public ObservableCollection<Labor> ListaLabores { get; set; }

}


public class Labor
{
    public int Dia { get; set; }

    public int Dato { get; set; }
}


public class MiConvertidor :IValueConverter {

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture) {

        int dato = (dato)value;

        if (Dato == 1) return new SolidColorBrush(Colors.Red);
        if (Dato == 2) return new SolidColorBrush(Colors.Blue);

        return Colors.Transparent;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) {
        throw new NotImplementedException();
    }
}

And here is the DataGrid that uses the data.

<DataGrid ItemsSource={Binding Trabajadores}>
    <DataGridTextColumn Header="Nombre" Binding="{Binding Nombre}"/>
    <DataGridTextColumn Header="Dia 1" Binding="{Binding Lista[0].Dia}">
        <DataGridTextColumn.CellStyle>
            <Style TargetType="DataGridCell">
                <Setter Property="Background" Value="{Binding Lista[0].Dato, Converter={StaticResource MiConvertidor}}"/>
            </Style>
        </DataGridTextColumn.CellStyle>
    </DataGridTextColumn>

    <DataGridTextColumn Header="Dia 2" Binding="{Binding Lista[1].Dia}">
        <DataGridTextColumn.CellStyle>
            <Style TargetType="DataGridCell">
                <Setter Property="Background" Value="{Binding Lista[1].Dato, Converter={StaticResource MiConvertidor}}"/>
            </Style>
        </DataGridTextColumn.CellStyle>
    </DataGridTextColumn>

    <DataGridTextColumn Header="Dia 3" Binding="{Binding Lista[2].Dia}">
        <DataGridTextColumn.CellStyle>
            <Style TargetType="DataGridCell">
                <Setter Property="Background" Value="{Binding Lista[2].Dato, Converter={StaticResource MiConvertidor}}"/>
            </Style>
        </DataGridTextColumn.CellStyle>
    </DataGridTextColumn>

</DataGrid>

Now I put part of the ViewModel that contains the property linked to the Datagrid:

public class TrabajadoresViewModel
{

    public ObservableCollection<Trabajador> Trabajadores{
        get{
            return new ObservableCollection<Trabajador>(){ 
                new Trabajador() {Nombre = "Nombre1", ListaLabores = new ObservableCollection<Labor>() {Dia = 1, Dato = 2} }
                new Trabajador() {Nombre = "Nombre2", ListaLabores = new ObservableCollection<Labor>() {Dia = 2, Dato = 1} }
                new Trabajador() {Nombre = "Nombre3", ListaLabores = new ObservableCollection<Labor>() {Dia = 3, Dato = 5} }
            };
        }
    }

}

What I want is not to have to use the cell style in each column of the DataGrid, putting it in a ResourceDictionary.

If I do so, the DataGrid would look like this:

<DataGrid ItemsSource={Binding Trabajadores}>
    <DataGridTextColumn Header="Nombre" Binding="{Binding Nombre}"/>
    <DataGridTextColumn Header="Dia 1" Binding="{Binding Lista[0].Dia}" CellStyle={StaticResource EstiloCelda}/>
    <DataGridTextColumn Header="Dia 2" Binding="{Binding Lista[1].Dia}" CellStyle={StaticResource EstiloCelda}/>
    <DataGridTextColumn Header="Dia 3" Binding="{Binding Lista[2].Dia}" CellStyle={StaticResource EstiloCelda}/>
</DataGrid>

And the style in the ResourceDictionary:

<Style x:Key="EstiloCelda" TargetType="DataGridCell">
    <Setter Property="Background" Value="{Binding Lista/Dato, Converter={StaticResource MiConvertidor}}"/>
</Style>

[EDITION 2]

I add a picture of what I want to achieve:

As you can see, if the data of the days is 1, the background is red. If the data is 2, the background is blue.

This works fine if I put the cell style in each column. If I put it in a ResourceDictionary using the '/' bar to indicate the current element of the collection, it looks like this:

As you can see, take the data from the first column and move it to the whole row, even if the day data of the other columns is different.