Surbrillance d'une cellule

Option Explicit
Dim cou As Long
Dim pos As String
Private Sub Worksheet_SelectionChange(ByVal sel As Range)
    If sel.Count > 1 Then Exit Sub
    If pos <> "" Then Range(pos).Font.Color = cou
    If sel = "oui" Then
        pos = sel.Address
        cou = sel.Font.Color
        sel.Font.Color = -11489280
    ElseIf sel = "non" Then
        pos = sel.Address
        cou = sel.Font.Color
        sel.Font.Color = -16776961
    Else
        pos = ""
    End If
End Sub