body {
    background: url("../img/bg1.png") no-repeat center fixed;
    background-size: cover;
    background-color: rgba(100, 146, 235, 0.7);
    min-height: 100vh; 
    margin: 0;
    overflow-y: auto;
    padding-top: 95px;
    padding-bottom: 80px;
}

/* 顶部白色横条 */
body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 95px;
    background: rgba(255,255,255,0.70);
    z-index: 4;
}
/*底部白色横条 */
body::after{
    content: "";
    position: fixed;
    bottom: 0;      /* 从底部定位，而不是顶部 */
    left: 0;
    width: 100%;
    height: 80px;
    background: rgba(210, 226, 242, 0.70);
    z-index: 4;
}
/* 全屏入场遮罩 */
.big {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: transparent; /* 去掉白色背景，完全透明 */
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 1;
  transition: opacity 0.8s ease;
  pointer-events: none; /* 透明背景不阻挡底下页面任何点击交互 */
}
/* 文字垂直居中排版 */
.big-text {
  text-align: center;
}
.big-text div {
  font-family: "SimHei", sans-serif;
  font-weight: 900;
  font-size: 240px;
  color: #000;
  margin: 12px 0;
  /* 文字逐个弹出动画 */
  opacity: 0;
  transform: translateY(30px);
  animation: textShow 0.8s ease forwards;
  /* 可选：如果黑字在蓝色背景上不够清晰，打开下面这行加个细白边 */
  text-shadow: 0 0 30px rgba(255,255,255,0.8);
}
/* 依次延迟每个文字出场 */
.big-text div:nth-child(1) { animation-delay: 0.4s; }
.big-text div:nth-child(2) { animation-delay: 0.8s; }
.big-text div:nth-child(3) { animation-delay: 1.2s; }

/* 文字弹出动画 */
@keyframes textShow {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
/* 退场隐藏类 */
.big.hide {
  opacity: 0;
  pointer-events: none;
}

/* 队徽 - 在白栏左侧内部 */
.logo_img {
    position: fixed;
    top: -60px;      
    left: 20px;      /* 左侧留边距 */
    z-index: 99;
}
.logo_img img {
    height: 230px;
    width: auto;
    display: block;
}

.logo_img2 {
    position: fixed;
    bottom: -34px;     /* 凸出白栏上方60px */
    left: 20px;
    z-index: 99;
}
.logo_img2 img {
    height: 150px;
    width: auto;
    display: block;
}

/* 中间蓝色轮播外框，定位居中，和你图里深蓝色区域匹配 */
.banner_swiper {
  position: relative;
  top: auto;
  left: auto;
  transform: none;
  margin: 20px auto;
  width: 72%;
  height: 76vh;
  overflow: hidden;
  border-radius: 6px;
  z-index: 2;
}
/* 图片横向容器 */
.swiper_wrap {
  display: flex;
  width: 100%;
  height: 100%;
  transition: transform 0.6s ease;
}
/* 单张图片容器 */
.swiper_item {
  flex-shrink: 0;
  width: 100%;
  height: 100%;
}
.swiper_item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
/* 左右切换按钮 */
.btn_prev, .btn_next {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: rgba(255,255,255,0.7);
  font-size: 20px;
  cursor: pointer;
  z-index: 6;
}
.btn_prev { left: 12px; }
.btn_next { right: 12px; }
/* 导航文字 - 右对齐 */
.menu_wrap {
    display: flex;
    gap: 40px;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 25px 40px;  /* 上下和左右内边距 */
    box-sizing: border-box;
    justify-content: flex-end;
    align-items: center;
    z-index: 10;
}
.menu_wrap p {
    margin: 0;
}
.menu_wrap span {
    font-size: 30px;
    font-family: "SimHei", "Microsoft YaHei", "PingFang SC", sans-serif;
    font-weight: 700;
    color: #333;
}
/* ===== 导航菜单微交互 ===== */
.menu_wrap span {
    font-size: 30px;
    font-family: "SimHei", "Microsoft YaHei", "PingFang SC", sans-serif;
    font-weight: 700;
    color: #333;
    /* 🔥 添加过渡效果 */
    transition: color 0.3s ease, transform 0.3s ease;
    /* 为下划线动画准备 */
    display: inline-block;
    position: relative;
    cursor: pointer;
}

/* 🔥 下划线从中间展开的动画（伪元素实现） */
.menu_wrap span::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    width: 0;
    height: 3px;
    background: #4A90D9;
    border-radius: 2px;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    transform: translateX(-50%);
}

/* 悬停时下划线从中间向两边展开 */
.menu_wrap span:hover::after {
    width: 100%;
    left: 0;
    transform: translateX(0);
}

/* 悬停时文字颜色变化 + 轻微上浮 */
.menu_wrap span:hover {
    color: #4A90D9;
    transform: translateY(-2px);
}

/* 点击时的反馈（瞬间缩小再回弹） */
.menu_wrap span:active {
    transform: scale(0.92);
    transition-duration: 0.1s;
}
/* 底部版权注释 靠右放置 */
.zhushi {
  position: fixed;
  bottom: 0;
  left: auto;
  width: 100%;
  padding: 0 40px;
  box-sizing: border-box;
  height: auto;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  z-index: 99;
  margin-top: 20px;
  margin-bottom: 20px;
}
.zhushi p {
  margin: 0;
  text-align: right;
}
.zhushi span {
  font-size: 16px;
  color: #333;
  line-height: 1.6;
}
  
.video_box {
  position: relative;
  top: auto;
  left: auto;
  transform: none;
  margin: 40px auto 40px;
  width: 73%;
  text-align: center;
  z-index: 2;
}
.video_box video {
  width: 100%;
  border-radius: 6px;
}
.video_box button {
    background-color: #4A90D9;    /* 按钮背景色 */
    color: #FFFFFF;               /* 文字颜色 */
    border: none;
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 16px;
    cursor: pointer;
    margin: 4px 6px;
    transition: 0.3s;
}

/* 鼠标悬停效果 */
.video_box button:hover {
    background-color: #2C6FB0;    /* 悬停时背景色 */
}