#colonnecentrale {position: absolute;
            z-index:1;
            /* top:50%;   */
            top:20px;
            left: 50%;
            width: 994px;
            height: 570px;
            /* margin-top: -285px;         */
            margin-left: -497px;
            border: 0px solid red;
            background-color: #414141;
            }
#navigateurs {position: absolute;
      z-index:1;
      top: 570px;
      margin-left: 10px;
      width: 970px;
      height: 20px;
      color: white;
      font-size: 9px;
      font-family: "Arial";
      text-align: center;
      }
#avertissement {position: absolute;
      z-index:99999;
      margin-top: 400px;
      margin-left: 30px;
      width: 199px;
      height: 150px;
      color: yellow;
      font-size: 14px;
      text-align: center;
      }