Sub ColorRows()
    Dim cell As Range, color1 As Variant, color2 As Variant, rowColor As Variant
    Dim letzeSpalte As Integer
    Dim i As Integer
 
    color1 = vbCyan
    color2 = vbWhite
 
    With ActiveSheet
 
        letzeSpalte = .Range("A:Z").SpecialCells(11).Column
 
        For Each cell In .Range("A4:A" & .Cells(Rows.Count, 1).End(xlUp).Row)
            If cell.Font.Bold Then
                rowColor = IIf(rowColor = color1, color2, color1)
            End If
 
            For i = 1 To letzeSpalte
 
                cell(1, i).Interior.Color = rowColor
 
            Next
 
        Next
    End With
End Sub