body {
  margin: 0;
  padding: 0;
}

#container {
  position: fixed;
  touch-action: none;
}
  .bottom-center-div {  
    position: absolute;  
    bottom: 0;  
    width: 100%;  
    text-align: center;  
    padding: 20px;  
    box-sizing: border-box;
    }
  .centered-div {
      position: fixed;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
    }

    .centered-div h2 {
      color: #FFFFFF;
      text-shadow: 3px 3px 5px rgba(0, 0, 0, 1); /* 水平偏移 2px，垂直偏移 2px，模糊半径 4px，颜色为半透明黑色 */
    }