/* 超小屏幕(<=575px) */
@media screen and (max-width:575px) {
  .head {
    display: none;
  }

  nav {
    position: fixed !important;
  }

  .nav-menu li a {
    font-size: 14px;
  }

  .nav-menu li a:hover {
    color: rgb(88, 224, 255);
    scale: 1.1;
    transition: 2s;
  }

  .burger {
    display: block;
  }

  .footer {
    margin-top: 40px;
    font-size: 15px;
    line-height: 50px;
    font-family: 'footer' !important;
    color: rgb(120 125 241);
  }

  .menu-box {
    display: none;
  }

  /* 小屏幕菜单显示位置为右侧抽屉形式 */
  .nav-menu {
    display: none;
    position: absolute;
    top: 80px;
    right: 0;
    bottom: 0;
    width: 30vw;
    height: 80vw;

    background-color: rgba(99, 123, 155, 0.445);
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;

    /* 动画 */
    transform: translatey(100%);
    transition: 0.4s ease-in-out;
  }

  /* 菜单打开时，滑到初始位置 */
  .nav-menu.open {
    margin-right: 10px;
    display: block;
    transform: translatey(0);
  }

  /* 每个菜单项默认看不到，向右移动20象素 */


  .nav-menu li {
    width: 46% !important;
    /* 上下间距 */
    margin: 5vh;
    transform: translateX(20px);
    opacity: 0;
  }

  /* 汉堡按钮被点开时，设置按钮过渡 */
  .burger.active div {
    transition: 0.3s ease-in-out 0.3s;
  }

  /* 第一条线旋转45度 */
  .burger.active .top-line {
    transform: rotate(45deg) translate(4px, 6px);
  }

  /* 第三条线旋转-45度 */
  .burger.active .bottom-line {
    transform: rotate(-45deg) translate(4px, -6px);
  }

  /* 中间线向右移动并变为透明 */
  .burger.active .middle-line {
    opacity: 0;
    transform: translateX(10px);
    transition: 0.3s ease-in-out;
  }



  /* 菜单项滑入动画 */
  @keyframes slideIn {
    from {
      transform: translateX(20px);
      opacity: 0;
    }

    to {
      transform: translateX(0);
      opacity: 1;
    }
  }


  body {
    background-color: white;
    background-image: none;
  }

  .nav {
    position: sticky;
  }

  .big_div {
    border: 0px;
    border-radius: 0;
  }

  .big_div_001 {
    display: none;
  }

  .big_div_004{
    display: none;
  }

  .big_div_002 {
    display: block;
    width: 100%;
    margin-top: 100px;
  }

  .big_div_002 .title {
    position: relative;
    top: 25px;
    font-size: 25px;
  }

  .big_div_003 {
    display: block;
    width: 100%;
    margin-top: 100px;
  }

  .big_div_003>.title {
    font-size: 25px;
    margin-bottom: 20px;
  }

  .big_div_003>span {
    color: black;
    font-size: 17px;
  }

  .big_div_003>p {
    margin: auto;
    width: 90%;
    text-align: start;
    text-indent: 2em;
    color: black;
    font-size: 15px;
    margin-bottom: 30px;
    margin-top: 20px;
  }

  .big_div_003>.kong {
    height: 10px;
  }

  .big_div_003>.img img {
    width: 100%;
    overflow: hidden;
    margin-bottom: 10px;
  }

  
  .small-box {
    border: 1px solid rgb(210, 210, 210);
    position: relative;
    width: 90%;
    height: 250px;
    margin: auto;
    margin-top: 50px;
    margin-bottom: 20px;
    box-shadow: 10px 10px 20px rgb(9 75 82 / 50%);
  }

  .small-box:hover {
    scale: 1.01;
  }

  .box-left {
    position: absolute;
    height: 70%;
    width: 30%;
    left: 30px;
    top: -30px;
  }

  .box-left img {
    margin-top: 30px;
    margin-bottom: 10px;
    border: 2px solid rgb(220, 156, 133);
    width: 100%;
  }

  .box-left span {
    color: rgb(80 111 200);
    margin-top: 10px;
    font-size: 18px;
    font-family: '宋体';
    font-weight: 600;
  }

  .box-right {
    position: absolute;
    right: 10px;
    top: 15px;
    width: 55%;
  }

  .box-right span{
    font-size: 20px;
  }

  .box-right p {
    margin-left: 15px !important;
    width: 90%;
    text-indent: 2em;
    text-align: start;
    font-size: 15px !important;
    font-family: 'totoro' !important;
    color: black;
    margin-top: 25px !important;
  }

  #first {
    display: none;
  }

  .head {
    height: 70px;
  }

  footer {
    margin-top: 10px;
    height: 50px;
  }

  #base {
    display: none;
  }

  #plot {
    display: none;
  }

}

/* 小屏幕(576px <= width <= 768px) */
@media screen and (min-width:576px) {
  #first {
    font-size: 18px;
  }

  .nav-menu li a {
    font-size: 15px;
  }

  footer {
    height: 50px;
  }

  .footer {
    font-size: 20px;
    line-height: 50px;
  }

  .box-right p {
    font-size: 10px;
    margin-top: 15px;
  }

  .box-left {
    margin-top: 25px;
  }

  #base p {
    width: 100%;
    text-indent: 2em;
    font-size: 23px;
  }

  #base span {
    font-size: 25px;
  }

  #base table {
    width: 100%;
  }

  .menu-button {
    width: 50px !important;
    height: 50px !important;
  }

  .menu-list {
    width: 150px !important;
    height: 200px !important;
  }

  .menu-list span {
    font-size: 19px !important;
  }

  .menu-list li {
    padding: 8px !important;
  }

  .menu-list .fa {
    width: 15px !important;
  }
}

/* 中屏幕(768px <= width <= 992px) */
@media screen and (min-width:768px) {
  #first {
    font-size: 20px;
  }

  .nav-menu li a {
    font-size: 17px;
  }

  footer {
    height: 50px;
  }

  .footer {
    font-size: 22px;
    line-height: 50px;
  }

  .box-right p {
    font-size: 10px;
    margin-top: 15px;
  }

  .box-left {
    margin-top: 30px;
  }

  #base p {
    width: 100%;
    text-indent: 2em;
    font-size: 25px;
  }

  #base span {
    font-size: 30px;
  }

  #base table {
    width: 100%;
  }

  .menu-button {
    width: 50px !important;
    height: 50px !important;
  }

  .menu-list {
    width: 150px !important;
    height: 200px !important;
  }

  .menu-list span {
    font-size: 20px !important;
  }

  .menu-list li {
    padding: 10px !important;
  }

  .menu-list .fa {
    width: 18px !important;
  }
}

/* 大屏幕(992px <= width <= 1200px) */
@media screen and (min-width:992px) {
  #first {
    font-size: 22px;
  }

  .nav-menu li a {
    font-size: 17px;
  }

  footer {
    height: 60px;
  }

  .footer {
    font-size: 25px;
    line-height: 60px;
  }

  .box-right p {
    font-size: 10px;
    margin-top: 15px;
  }

  .box-left {
    margin-top: 30px;
  }

  #base p {
    width: 90%;
    text-indent: 2em;
    font-size: 30px;
  }

  #base span {
    font-size: 30px;
  }

  #base table {
    width: 80%;
  }

  .menu-button {
    width: 50px !important;
    height: 50px !important;
  }

  .menu-list {
    width: 150px !important;
    height: 200px !important;
  }

  .menu-list span {
    font-size: 20px !important;
  }

  .menu-list li {
    padding: 10px !important;
  }

  .menu-list .fa {
    width: 18px !important;
  }
}

/* 超大屏幕(width >= 1200px) */
@media screen and (min-width:1200px) {
  #first {
    font-size: 25px;
  }

  footer {
    height: 80px;
  }

  .footer {
    font-size: 30px;
    line-height: 80px;
  }

  .box-right p {
    font-size: 15px;
    margin-top: 20px;
  }

  .box-left {
    margin-top: 30px;
  }

  #base p {
    width: 90%;
    text-indent: 2em;
    font-size: 30px;
  }

  #base span {
    font-size: 30px;
  }

  #base table {
    width: 80%;
  }

  .menu-button {
    width: 50px !important;
    height: 50px !important;
  }

  .menu-list {
    width: 150px !important;
    height: 200px !important;
  }

  .menu-list span {
    font-size: 20px !important;
  }

  .menu-list li {
    padding: 10px !important;
  }

  .menu-list .fa {
    width: 18px !important;
  }
}