* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  body {
    min-height: 100vh;
    /* IE兼容 */
    zoom: 1;
  }

  /* 全屏欢迎层 - 兼容IE的居中方案 */
  #welcomeFull {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(255,255,255,0.8);
    z-index: 99999999999;
    /* 替换flex，用IE兼容的定位居中 */
    text-align: center;
    /* 过渡效果兼容IE10+ */
    -webkit-transition: all 0.6s ease;
    -moz-transition: all 0.6s ease;
    -ms-transition: all 0.6s ease;
    transition: all 0.6s ease;
  }
  /* 兼容IE的垂直居中辅助类 */
  #welcomeFull .center-wrap {
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    overflow: hidden;
  }
  /* 收起后的样式 */
  #welcomeFull.hide {
    width: 60px;
    height: 60px;
    right: 20px;
    left: auto;
    top: 20px;
    border-radius: 50%;
    background: url(../images/bg.jpg);
    background: #c72e25;
    cursor: pointer;
    display: none;/* 隐藏 可去除 */
  }

  /* 媒体内容（图片/视频）- 修复显示不全+兼容IE */
  .welcome-media {
    /* 替换object-fit:cover，用IE兼容的缩放方案 */
    
    width: 100%;
    height: 70%;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    /* 居中 */
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    top: 50%;
    left: 50%;
  }
  #welcomeFull.hide .welcome-media {
    display: none;
  }

  /* 提前关闭按钮 - 全屏时显示 */
  .close-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    background: rgba(0,0,0,0.5);
    color: #fff;
    border-radius: 50%;
    cursor: pointer;
    font-size: 16px;
    z-index: 10;
  }
  #welcomeFull.hide .close-btn {
    display: none;
  }

  /* 右上角文字（收起后显示） */
  .spring-text {
    display: none;
    color: #fff;
    font-size: 12px;
    text-align: center;
    white-space: nowrap;
    /* IE垂直居中 */
    line-height: 60px;
  }
  #welcomeFull.hide .spring-text {
    display: block;
  }

 .header_bg{
   padding-top:135px;
   background:url('../images/bg09.png?version=1.1') no-repeat;
   background-size:100% 100%;