CdG’s deck is coloured as such to assist pilots in a night landing. I asked a French Pilot once, apparently the NVG’s they use show the deck and pilots aim for the dark strip between the lighter bits as that is the landing strip. Makes sence to me, same reason why the Imperial Japanese Navy painted their decks really light colours which aided the USN during the battle of Midway… Aim for sand coloured deck in a dive and you cant miss!