Sub Worksheet_Change(ByVal Target As Range)
With Target
If .CountLarge > 1 Then Exit Sub
If .Address(0, 0) <> "A1" Then Exit Sub
Dim cf&, ct&, np$, tp As Byte, b As Boolean
If .Value < 10 Then
'fond rouge, texte jaune, gras italique
cf = RGB(255, 0, 0): ct = RGB(255, 255, 0)
np = "Calibri": tp = 18: b = -1
Else
cf = RGB(255, 255, 255): ct = RGB(0, 0, 0)
np = "Arial": tp = 8: b = 0
End If
.Interior.Color = cf
With .Font
.Color = ct: .Name = np: .Size = tp
.Bold = b: .Italic = b
End With
End With
End Sub