Format condition

See file Attached
Worksheet Events are used. Range B1:E6 is used. Can be changed.
code

Dim PreValue As Variant
Private Sub Worksheet_SelectionChange(ByVal Target As Range)

If Not Intersect(Target, Range("B1:C6")) Is Nothing And Target.Cells.Count = 1 Then
PreValue = Target.Value
End If

End Sub
Private Sub Worksheet_Change(ByVal Target As Range)

If Not Intersect(Target, Range("B1:E6")) Is Nothing And Target.Cells.Count = 1 Then
    If PreValue = "" Then
    
    With Target.Interior
        .Pattern = xlSolid
        .PatternColorIndex = xlAutomatic
        .ThemeColor = xlThemeColorAccent3
        .Color = 65535
        .TintAndShade = 0
    End With
    
    ElseIf PreValue <> Target.Value And Target.Value <> "" Then
    
    With Target.Interior
        .Pattern = xlSolid
        .PatternColorIndex = xlAutomatic
        .ThemeColor = xlThemeColorAccent3
        .TintAndShade = 0.599993896298105
        .PatternTintAndShade = 0
    End With

    End If

End If

End Sub