body 
{
    background-color: #f8f8f8;
    font-family: "Microsoft YaHei", sans-serif;
}
@media (min-width: 1400px) {
    .container {
        max-width: 1400px;
    }
}
p
{
    margin:0px;
}
a {
    color: #333;
    text-decoration: none;
}
a:hover {
    color: #f60;
    text-decoration: underline;
}
.screen-1 a, .footer {
    font-size: 12px;
}

.nav-container {
    background-color: #0090ce;
    width: 100%;
}
.screen-3 .navbar {
    background-color: transparent;
}
.screen-3 .navbar .nav-link {
    color: #fff;
    position: relative;   
   
    padding:15px;
   display:block;
}
.screen-3 .navbar .nav-link::after {
    content: ' ';
    position: absolute;
    right: 0;     
    height: 20px;
    width: 1px;
    display:block;
    background:#fff;
    top:calc(50% - 10px);
}

.screen-3 .navbar .nav-link:hover, .screen-3 .navbar .nav-link.active {
    background-color: #0074a6;
    color:#fff;
}
.screen-3-5 {
    background-color: #fff;
    box-shadow:0 1px 2px rgba(0,0,0,.1);
   
}
.screen-3-5 .nav-tabs {
    border-bottom: none;
}

.screen-3-5 .nav-tabs .nav-item
{
    margin-bottom:0px;
}
.screen-3-5 .nav-tabs .nav-link {
    color: #6c6c6c;
    background-color: #fff;
    border: none;
    padding: 10px 20px;
    margin-right: 5px;
    display: flex;
    align-items: center;
    border-radius:0px;
}
.screen-3-5 .nav-tabs .nav-link:hover {
    background-color: #e9ecef;
}
.screen-3-5 .nav-tabs .nav-link.active {
    background-color: #e9ecef;
}
.screen-3-5 .nav-tabs .nav-link .fa-chevron-down {
    margin-left: 10px;
}
.screen-3-5 .nav-tabs .nav-link.active .fa-chevron-down {
    display: none;
}
.screen-3-5 .nav-tabs .nav-link .fa-chevron-up {
    display: none;
    margin-left: 10px;
}
.screen-3-5 .nav-tabs .nav-link.active .fa-chevron-up {
    display: inline;
}
.screen-3-5 .tab-content {
   
    background-color: #fff;
}
.tab-content a{
    display:inline-block;
    margin-right:8px;
    font-size:14px;
}
.tab-content .active{
    padding:15px 10px;
    background:#e9ecef;
}


.screen-4 .carousel, .screen-4 .carousel-inner, .screen-4 .carousel-item {
    height: 300px;
}
.screen-4 .carousel-item img {
    object-fit: cover;
    height: 100%;
}
.screen-4 .hot-textbooks {
    height: 100%;
    overflow-y: auto;
}
.screen-4 .hot-textbooks a {
    display: block;
    margin-bottom: 10px;
	overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.right-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  padding: 0;
  margin: 0;
}

.right-links a {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 90px;
  padding: 16px 8px;
  background-color: #0090ce;
  color: white;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  text-align: center;
  border-radius: 8px;
  transition: background-color 0.25s ease;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.right-links a i {
  color: white;
  margin-bottom: 8px;
  font-size: 24px; 
}



.right-links a:hover {
  background-color: #f60;
}

.right-links a:hover i {
  color: white;
}


.hot-textbooks h5 {
  position: relative;
  display: inline-block;
  margin: 0 0 16px 0;
  padding-bottom: 8px;
  font-size: 16px;
  font-weight: 600;
  color: #333;
  line-height: 1.4;
  width:100%; 
  border-bottom: 1px solid #e0e0e0;
  
  
}

.hot-textbooks h5::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -1px; 
  width: 32px; 
  height: 2px;
  background-color: #0090ce;
  border-radius: 1px;
}

 ul,ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

.hot-textbooks li {
  margin-bottom: 10px;
  line-height: 1.5;
  border-bottom:1px dashed #ccc;
}

.hot-textbooks li:last-child {
  margin-bottom: 0;
}

.hot-textbooks a {
  
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s ease;
}

.hot-textbooks a:hover {
 
  text-decoration: underline;
}


.screen-5 .section-title {
    font-size: 24px;
    margin-bottom: 10px;
}
.divider{
     margin-bottom: 10px;
}


.subject-links,.grade-links
{
    font-size:14px;
}
.subject-links span,.grade-links span{
    font-weight:700;
    color:#0090ce;
}

.subject-links a, .grade-links a {
    display: inline-block;
   
    padding: 0px 9px;
    color: #6c6c6c;
    position:relative;
}
.subject-links a::after,.grade-links a::after{
    content:'';
    position:absolute;
    width:1px;
    height:12px;
    top:5px;
    right:0px;
    background:#ccc;
}
.subject-links a:last-child::after,.grade-links a:last-child::after{
    display:none;
}

.divider-blue {
    border-top: 2px solid #007bff;
    
}
.divider-green {
    border-top: 2px solid #28a745;
}
.divider-purple
{
    border-top:2px solid #7143a9
}
.divider-red
{
    border-top:2px solid #c90210;
}
.section-blue
{
    color:#0074a6;
}
.section-green
{
    color:#28a745
}
.section-purple
{
    color:#7143a9;
}
.section-red
{
    color:#c90210;
}


 .subject-links a:hover, .grade-links a:hover {
    color: #f60;
    text-decoration: underline;
}
.textbook-item
{
    margin-bottom:12px;
    border-bottom:2px dashed #ccc;
    padding-bottom:12px;
}
.textbook-item a{
    font-size:12px;
    text-align:center;
    width:100%;
    display:block;
}
.textbook-item .img-link {
  display: block;
  width: 100%;
  margin-bottom: 10px;
  border: 2px solid #e0e0e0;
  border-radius: 6px;
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

.textbook-item .img-link:hover {
  border-color: #0090ce;
  box-shadow: 0 6px 16px rgba(0, 144, 206, 0.2);
  transform: translateY(-2px);
}

.textbook-item .img-link img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 6px; 
  transition: transform 0.3s ease;
}

.textbook-item .img-link:hover img {
  transform: scale(1.05);
}

 

.footer {
    text-align: center;
    padding: 20px 0;
    background-color: #fff;
}
.logo a{
    display:inline-block;
}
.logo a img{
    max-height:45px;

}

.search-form {
  display: flex;
  width: 100%;
  max-width: 400px;
  height: 40px; 
  margin: 0 auto;
}

.search-form .form-control {
  flex: 1;
  height: 100%;
  padding: 0 12px;
  font-size: 14px;
  border: 2px solid #0090ce;
  border-right: none;
  border-radius: 6px 0 0 6px;
  outline: none;
  box-sizing: border-box;
}

.search-form .search-btn {
  width: 80px;
  height: 100%;
  background-color: #0090ce;
  color: white;
  font-size: 14px;
  font-weight: 500;
  border: none;
  border-radius: 0 6px 6px 0;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.search-form .search-btn:hover {
  background-color: #007bb5;
}

.search-form .search-btn:active {
  background-color: #006a99;
}

.navbar
{
    padding-top:0px;
    padding-bottom:0px;
}

.nava
{
    font-size:13px;
}

.select-box {
    margin-bottom: 2rem;
    
}

.hover-tabs-nav {
    display: flex;
    justify-content: start;
    flex-wrap: wrap;
    gap: 8px;
    
    padding: 0.5rem 0;    
    border-bottom: 1px solid #dee2e6;
    font-size:14px;
    color:#333;
}
.tab-name{
        font-weight:700;
        color:#17a2b8;
}

.tab-btn {       
    text-decoration: none;    
    
}


.tab-contents .tab-item {
    display: none;
    padding: 0.5rem 1rem;
    background: #ffffff;
    border: 1px solid #dee2e6;
    border-top:0px;
    min-height: 80px;
}
.tab-contents .tab-item a{
    font-size:13px;
    margin-right:5px;
}

.tab-contents .tab-item.active {
    display: block;
}

.big-title h1{
    font-size:1.5em;
    font-weight:700;
}



.left_menu ,.right_content
{
   padding:10px;
}

.book_thumb img
{
    max-width:100%;
    display:block;
    margin:0 auto;
}
.big_info
{
    padding-bottom:6px;
    margin-bottom:6px;
    font-size:1em;
    color:#000;
    border-bottom:1px solid #ccc;
}





.left_item_box {
    padding-top:10px;
    padding-bottom:10px;
    margin-bottom: 10px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
    
}


.left_item_box h3 {
    font-size: 15px;
    font-weight: 600;
    color: #333;
    margin: 0 0 12px 0;
    padding-bottom: 8px;
    border-bottom: 2px solid #007bff;
    position: relative;
    line-height: 1.4;
}


.left_item_box h3::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 40px;
    height: 2px;
    background: #0056b3;
}


.left_item_box ul {
    list-style: none;
    padding: 0;
    margin: 0;
}


.left_item_box ul li {
    margin-bottom: 10px;
    padding-bottom:4px;
    position: relative;
    padding-left: 20px;
    line-height: 1.5;
    border-bottom:1px dashed #ccc;
}


.left_item_box ul li::before {
    font-family: "Font Awesome 5 Free";
    font-weight: 900;
    content: "\f019"; 
    color: #007bff;
    position: absolute;
    left: 2px;
    top: 2px;
    font-size: 12px;
}


.left_item_box ul li a {
    display: block;  
    width:100%;   
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size:14px;
    text-decoration:none;
}

.big_info {
    background: #ffffff;
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
    border: 1px solid #eef1f6;
    transition: all 0.3s ease;
}

.big_info:hover {
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
    transform: translateY(-1px);
}


.big_info h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: #222;
    margin: 0 0 16px 0;
    line-height: 1.3;
    position: relative;
    padding-bottom: 12px;
}

.big_info h2::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #007bff, #0056b3);
    border-radius: 2px;
}


.big_info .infos {
    font-size: 1rem;
    color: #555;
    margin: 0;
    line-height: 1.6;
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    align-items: center;
}


.big_info .infos a {
    color: #007bff;
    text-decoration: none;
    font-weight: 500;
    padding: 4px 10px;
    border-radius: 6px;
    background: rgba(0, 123, 255, 0.1);
    transition: all 0.2s ease;
    white-space: nowrap;
}

.big_info .infos a:hover {
    background: #007bff;
    color: #ffffff;
    text-decoration: none;
}


.big_info .infos::before,
.big_info .infos span {
    color: #777;
    font-weight: 500;
}


.big_info .infos a:nth-child(1) { 
    background: rgba(40, 167, 69, 0.1);
    color: #28a745;
}

.big_info .infos a:nth-child(1):hover {
    background: #28a745;
    color: #fff;
}

.big_info .infos a:nth-child(2) { /* 科目 */
    background: rgba(255, 193, 7, 0.1);
    color: #ffc107;
}

.big_info .infos a:nth-child(2):hover {
    background: #ffc107;
    color: #212529;
}

.big_info .infos a:nth-child(3) { /* 年级 */
    background: rgba(23, 162, 184, 0.1);
    color: #17a2b8;
}

.big_info .infos a:nth-child(3):hover {
    background: #17a2b8;
    color: #fff;
}














.right_menu {
    padding: 20px;
    background: #ffffff;
    border-radius: 10px;
    box-shadow: 0 3px 12px rgba(0, 0, 0, 0.05);
    border: 1px solid #e9ecef;
    height: fit-content;
}


.right_menu h3 {
    font-size: 1.35rem;
    font-weight: 600;
    color: #222;
    margin: 0 0 18px 0;
    padding-bottom: 10px;
    border-bottom: 2px solid #007bff;
    position: relative;
    line-height: 1.4;
}

.right_menu h3::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 45px;
    height: 2px;
    background: #0056b3;
    border-radius: 1px;
}


.right_menu pre {
    background: #f8f9fa;
    border: 1px dashed #ced4da;
    border-radius: 8px;
    padding: 16px;
    margin: 0;   
    font-size: 1rem;
    line-height: 1.5;
    color: #2c3e50;
    white-space: pre-wrap;
    word-wrap: break-word;
    overflow-x: auto;
    
    overflow-y: auto;
}








.right_downloads {
    background: #ffffff;
    border-radius: 12px;
    padding: 20px;
    margin-top: 24px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.07);
    border: 1px solid #e8f0fe;
    text-align: center;
    transition: all 0.3s ease;
}

.right_downloads:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 123, 255, 0.15);
    border-color: #007bff;
}


.right_downloads h3 {
    font-size: 16px;
    font-weight: 700;
    color: #1a1a1a;
    margin: 0 0 18px 0;
    padding-bottom: 10px;
    position: relative;
    display: inline-block;
    line-height: 1.4;
}

.right_downloads h3::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: 0;
    width: 50px;
    height: 3px;
    background: linear-gradient(90deg, #28a745, #1e7e34);
    border-radius: 2px;
    transform: translateX(-50%);
}


.right_downloads .download-box {
    display: flex;
    justify-content: center;
    gap: 14px;
    flex-wrap: wrap;
    margin-top: 8px;
}


.right_downloads .download-box .btn {
    
    padding: 10px 12px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    text-transform: none;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}


.right_downloads .download-box .download {
    background: linear-gradient(135deg, #28a745, #20c997);
    border: none;
    color: #fff;
    box-shadow: 0 4px 12px rgba(40, 167, 69, 0.3);
}

.right_downloads .download-box .download:hover {
    background: linear-gradient(135deg, #218838, #1baa80);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(40, 167, 69, 0.4);
}


.right_downloads .download-box .btn:nth-child(2) {
    background: linear-gradient(135deg, #007bff, #0069d9);
    border: none;
    color: #fff;
    box-shadow: 0 4px 12px rgba(0, 123, 255, 0.3);
}

.right_downloads .download-box .btn:nth-child(2):hover {
    background: linear-gradient(135deg, #0062cc, #0056b3);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 123, 255, 0.4);
}


.right_downloads .download-box .download::before {
    font-family: "Font Awesome 5 Free";
    font-weight: 900;
    content: "\f019"; 
    font-size: 1.1em;
}

.right_downloads .download-box .btn:nth-child(2)::before {
    font-family: "Font Awesome 5 Free";
    font-weight: 900;
    content: "\f059"; 
    font-size: 1.1em;
}






/* 弹窗 */

/* 模态框背景遮罩 */
.download-modal {
    display: none; /* 默认隐藏 */
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px); /* 毛玻璃效果 */
    animation: fadeIn 0.3s ease;
    justify-content: center;
    align-items: center;
    padding: 15px;
    box-sizing: border-box;
}

/* 模态内容卡片 */
.download-modal .modal-content {
    background: #ffffff;
    border-radius: 16px;
    width: 100%;
    max-width: 340px;
    padding: 24px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    position: relative;
    text-align: center;
    animation: zoomIn 0.3s ease;
    border: 1px solid #e0e0e0;
}

/* 关闭按钮 */
.download-modal .close-btn {
    position: absolute;
    top: 2px;
    right: 2px;
    font-size: 1.5rem;
    font-weight: bold;
    color: #aaa;
    cursor: pointer;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s ease;
}

.download-modal .close-btn:hover {
    background: #f1f1f1;
    color: #ee6e73;
}

/* 标题 */
.download-modal h4 {
    margin: 0 0 12px 0;
    font-size: 14px;
    font-weight: 400;
    color: #222;
}

/* 二维码容器 */
.download-modal .qrcode {
    margin: 0 auto 10px;
    padding: 12px;
    background: #f9f9f9;
    border-radius: 12px;
    display: inline-block;
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.05);
}

.download-modal .qrcode img {
    width: 180px;
    height: 180px;
    border-radius: 8px;
}

/* 提示文字 */
.download-modal .tip {
    font-size: 12px;
    color: #555;
    margin: 0 0 10px 0;
    line-height: 1.5;
}

/* PC 下载链接区域 */
.download-modal .pc-link p {
    margin: 0 0 10px 0;
    font-size: 0.9rem;
    color: #666;
}

.download-modal .btn-pc-download {
    display: inline-block;
    background: linear-gradient(135deg, #007bff, #0056b3);
    color: #fff;
    text-decoration: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 123, 255, 0.3);
}

.download-modal .btn-pc-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 123, 255, 0.4);
    background: linear-gradient(135deg, #0056b3, #004494);
}

/* 动画 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes zoomIn {
    from { transform: scale(0.8); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}





.relation_box  {
    background: #ffffff;
    border-radius: 12px;
    padding: 10px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
    border: 1px solid #eef2f7;
    margin-top: 24px;
}

.relation_box .relation-tab-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 18px;
    padding-bottom: 12px;
    border-bottom: 1px solid #e0e0e0;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
}

.relation_box .relation-tab-nav::-webkit-scrollbar {
    display: none;
}

.relation_box .relation-tab-btn {
    padding: 10px 16px;
    font-size: 0.95rem;
    font-weight: 500;
    color: #555;
    background: #f8f9fa;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: fit-content;
}

.relation_box .relation-tab-btn:hover {
    background: #e9ecef;
    color: #007bff;
}

.relation_box .relation-tab-btn.active {
    background: #007bff;
    color: #ffffff;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(0, 123, 255, 0.3);
}

.relation_box .relation-tab-content {
    min-height: 160px;
}

.relation_box .relation-tab-pane {
    display: none;
    animation: fadeIn 0.4s ease;
}

.relation_box .relation-tab-pane.active {
    display: block;
}

.relation_box .relation-link-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 14px 12px; 
    grid-template-columns: repeat(4, 1fr); 
}


.relation_box .relation-link-list li {
    margin: 0;
    border-bottom:1px dashed #ccc;
    position: relative;
    line-height: 1.6;
    min-height: 36px;
    display: flex;
    align-items: center;
}




.relation_box .relation-link-list a {
    color: #333;
    text-decoration: none;
    font-size: 14px;
    display: block;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    transition: color 0.2s ease;
    flex: 1;
}

.relation_box .relation-link-list a:hover {
    color: #007bff;
    text-decoration: underline;
}


.col-12.text-center {
    padding: 4rem 1rem;
    background: linear-gradient(135deg, #0090ce 0%, #4b2176 100%);
    color: #ffffff;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
    border-radius:20px 20px;
    position: relative;
    overflow: hidden;
}

.col-12.text-center::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><circle cx="20" cy="20" r="2" fill="rgba(255,255,255,0.1)"/><circle cx="80" cy="80" r="2" fill="rgba(255,255,255,0.1)"/></svg>') repeat;
    opacity: 0.3;
    pointer-events: none;
}

.web-title {
    font-size:2.6rem;
    font-weight: 700;
    margin: 0 0 1rem;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    letter-spacing: -0.5px;
    position: relative;
    display: inline-block;
}


.web-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: #ffffff;
    border-radius: 2px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.web-info {
    font-size: 1.05rem;
    line-height: 1.7;
    margin: 0 auto;
    max-width: 90%;
    opacity: 0.95;
    font-weight: 400;
}


@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}


.col-12.mt-2 {
    padding: 2rem 1rem;
    background: #f8f9fa;
    border-radius: 16px;
    margin-top: -2rem !important; 
    position: relative;
    z-index: 1;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
}

.sub-items {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
    max-width: 1200px;
    margin: 0 auto;
}

.one-sub-item {
    flex: 1;
    min-width: 180px;
    max-width: 220px;
    background: #ffffff;
    padding: 1.8rem 1rem;
    border-radius: 16px;
    text-align: center;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid rgba(0, 0, 0, 0.05);
    position: relative;
    overflow: hidden;
}


.one-sub-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.15);
    border-color: transparent;
}

.one-sub-item::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
    background: linear-gradient(90deg, #667eea, #764ba2);
    border-radius: 16px 16px 0 0;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.one-sub-item:hover::before {
    opacity: 1;
}

.one-sub-item .num {
    font-size: 2.5rem;
    font-weight: 800;
    color: #667eea;
    margin: 0 0 0.5rem;
    line-height: 1;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.one-sub-item .text {
    font-size: 1rem;
    color: #555;
    margin: 0;
    font-weight: 500;
    letter-spacing: 0.3px;
}


.navbar-light .navbar-toggler-icon {
  background-image:url("data:image/svg+xml,%3csvg viewBox='0 0 30 30' xmlns='http://www.w3.org/2000/svg'%3e%3cpath stroke='rgba(255, 255, 255, 1)' stroke-width='2' stroke-linecap='round' stroke-miterlimit='10' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e")
}

.navbar-toggler
{
    border:none !important;
}


#back-to-top {
    position: fixed;
    right: 20px;
    bottom: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 6px 16px rgba(102, 126, 234, 0.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1000;
    outline: none;
}


#back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(102, 126, 234, 0.4);
    background: linear-gradient(135deg, #5a6fd8, #6a4190);
}


#back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}


#back-to-top i {
    animation: float 2s ease-in-out infinite;
}


@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-4px); }
}


.ziliao-detail img{
    max-width:250px;
    border:1px solid #cfcfcf;
    padding:2px;
    border-radius:3px;
}
.pagenation {
    text-align: center;
    margin: 40px auto 20px;
}

.pagenation ul {
    display: inline-flex;
    list-style: none;
    padding: 0;
    margin: 0;
    border-radius: 50px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    background: #fff;
    border: 1px solid #e0e0e0;
}

.pagenation ul li {
    float: left;
}

.pagenation ul li a,
.pagenation ul li span {
    display: block;
    min-width: 44px;
    height: 44px;
    line-height: 44px;
    padding: 0 16px;
    text-decoration: none;
    color: #555;
    font-size: 15px;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}


.pagenation ul li span.current,
.pagenation ul li a.current,
.pagenation ul li.active a,
.pagenation ul li.active span {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff !important;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.4);
}


.pagenation ul li a:hover {
    background: #f8f9fa;
    color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}


.pagenation ul li a.prev,
.pagenation ul li a.next {
    font-weight: bold;
    color: #667eea;
}

.pagenation ul li a.prev:hover,
.pagenation ul li a.next:hover {
    background: #667eea;
    color: #fff !important;
}


.pagenation ul li.disabled a,
.pagenation ul li.disabled span {
    color: #bbb !important;
    cursor: not-allowed;
    background: #f5f5f5;
}

.ziliao-detail
{
    font-size:14px;
    line-height:1.8;
}

.zl_title
{
    font-size:1.8em;
    font-weight:700;
}



@media (max-width: 576px) {
    .pagenation ul {
        border-radius: 30px;
    }
    .pagenation ul li a,
    .pagenation ul li span {
        min-width: 38px;
        height: 38px;
        line-height: 38px;
       padding: 0 12px;
        font-size: 14px;
    }
}


@media (prefers-color-scheme: dark) {
    .pagenation ul {
        background: #2d2d2d;
        border: 1px solid #444;
    }
    .pagenation ul li a,
    .pagenation ul li span {
        color: #ddd;
    }
    .pagenation ul li a:hover {
        background: #3a3a3a;
    }
}



@media (min-width: 769px) {
    .sub-items {
        justify-content: space-between;
    }
    .one-sub-item {
        flex: 0 1 calc(25% - 1.5rem);
    }
}

@media (max-width:1366px)
{
.relation_box .relation-link-list{grid-template-columns: repeat(2, 1fr);}

    .zl_title
{
    font-size:1.6em;
    font-weight:700;
}
    .left_item_box h3
    {
        font-size:14px;
    }
.right_downloads h3
{
    font-size:15px;
}
    .big-title h1
    {
        font-size:1.4rem;
    }
    .screen-3 .navbar .nav-link
    {
        font-size:14px;
    }

    .web-title
    {
        font-size:2.3rem;
    }
    .web-info
    {
        font-size:14px;
    }
    .one-sub-item .num
    {
        font-size:2rem;
    }
    .big_info h2
    {
        font-size:1.25rem;
    }
    .right_menu h3
    {
        font-size:1.1rem;
    }

    .left_item_box ul li a
    {
        font-size:12px;
    }
}

@media (max-width:1280px)
{
    .web-title 
    {
        font-size:2.1rem;
    }

    .zl_title
    {
        font-size:1.4em;
        font-weight:700;
    }
}







@media (max-width: 992px) {

    .zl_title
{
    font-size:1.3em;
    font-weight:700;
}
.ziliao-detail
{
    font-size:13px;
}

   .title-box,.right_content
   {
    width:100%;
    max-width:100%;

   }
    .navbar
    {
        padding-left:0px;
    }
    .screen-3 .navbar .nav-link::after
    {
        display:none;
    }
    .relation_box .relation-tab-container { padding: 6px; }
    .relation_box .relation-tab-btn { padding: 8px 14px; font-size: 0.9rem; }

    .relation_box .relation-link-list {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .relation_box .relation-link-list a {
        font-size: 13px;
    }
.screen-3 .navbar .nav-link
{
    padding:5px 0px;
}
.nav-item
{
    border-bottom:1px dashed #fff;
}
    .one-sub-item {
        padding: 1.5rem 0.8rem;
        min-width:120px;
    }
    .one-sub-item .num {
        font-size: 1.68rem;
    }
.one-sub-item .text
{
    font-size:14px;
}

     .right_downloads {
        padding: 18px;
        margin-top: 20px;
    }

    .right_downloads h3 {
        font-size: 13px;
        margin-bottom: 16px;
    }

    .right_downloads .download-box .btn {
        min-width: 130px;
        padding: 9px 16px;
        font-size: 0.95rem;
    }

    .right_menu h3 {
        font-size: 1.125rem;
        margin-bottom: 16px;
        padding-bottom: 8px;
    }

    .right_menu pre {
        font-size: 14px;
        padding: 10px;
    }

     .big_info {
        padding: 20px;
        margin-bottom: 20px;
    }

    .big_info h2 {
        font-size: 1.4rem;
        padding-bottom: 10px;
    }

    .big_info h2::after {
        width: 50px;
        height: 3px;
    }

    .big_info .infos {
        font-size: 0.95rem;
        gap: 12px;
    }

    .big_info .infos a {
        padding: 3px 8px;
        font-size: 0.9rem;
    }

    .hot-textbooks
    {
        width:100%;
        max-width:100%;
        margin-bottom:10px;
        display:block;
        height:auto;
        flex:none;
    }
    .hot-slide
    {
       width:100%;
        max-width:100%;
        margin-bottom:10px;
        display:block;
        height:auto;
        flex:none;
    }
    .right-links
    {
        width:100%;
        display: grid;
        max-width:100%;
        flex:1;
        padding-left:15px;
        padding-right:15px;
    }
.subject-links span, .grade-links span
{
    display:block;
    margin-bottom:5px;

}
    .subject-links a, .grade-links a
    {
        font-size:13px;
        padding-left:0px;
        margin-bottom:3px;
    }
}



.list_jub{
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.list_jub a{
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 16px;
    font-size: 14px;
    color: #fff;
    background: #a1aab7;
    border-radius: 20px;
    text-decoration: none;
    transition: all .2s ease;
    white-space: nowrap;
}

.list_jub a:hover,.list_jub a.active{
    background: #409eff;
    color: #fff;
}

@media (max-width: 991px){
    .list_jub a{
        font-size: 13px;
        padding: 7px 14px;
    }
}

@media (max-width: 575px){
    .list_jub{
        gap: 8px;
    }
    .list_jub a{
        font-size: 12px;
        padding: 6px 12px;
        border-radius: 16px;
    }
}



@media (max-width: 768px) {

    .zl_title
{
    font-size:1.2em;
    font-weight:700;
}


     body, .screen-1 a, .screen-3 .navbar, .screen-5 .section-title, .footer {
        font-size: 14px;
    }
    .screen-3 .navbar-nav {
        background-color: #0090ce;
    }
    .screen-3-5 .nav-tabs .nav-link {
        font-size: 14px;
        padding: 8px 15px;
    }
#back-to-top {
        width: 44px;
        height: 44px;
        right: 16px;
        bottom: 20px;
        font-size: 1.2rem;
    }

    .relation_box .relation-tab-container { padding: 4px; margin-top: 10px; }
    .relation_box .relation-tab-nav { gap: 6px; }
    .relation_box .relation-tab-btn { padding: 7px 12px; font-size: 0.85rem; }
   .relation_box .relation-link-list {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .relation_box .relation-link-list li {
        padding-left: 20px;
    }

    .relation_box .relation-link-list a {
        font-size: 12px;
        white-space: normal;
        line-height: 1.5;
    }

    .big_info {
        padding: 16px;
        border-radius: 10px;
    }

    .big_info h2 {
        font-size: 1.3rem;
        margin-bottom: 14px;
    }

    .big_info .infos {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
        font-size: 0.9rem;
    }

    .big_info .infos a {
        display: inline-block;
        width: auto;
    }


    .col-12.text-center {
        padding: 3rem 1rem;
        border-radius: 16px 16px;
    }

    .left_item_box {
        padding: 12px;
        margin-bottom: 16px;
    }

    .left_item_box h3 {
        font-size: 13px; 
        margin-bottom: 10px;
        padding-bottom: 6px;
    }

    .left_item_box h3::after {
        width: 32px;
    }

    .left_item_box ul li {
        margin-bottom: 8px;
        padding-left: 18px;
        font-size: 0.925rem; 
    }

    .left_item_box ul li::before {
        font-size: 0.85em;
        top: 3px;
    }


    .right_menu {
        padding: 16px;
        margin-top: 20px;
    }

    .right_menu h3 {
        font-size: 1.2rem;
        margin-bottom: 14px;
    }

    .right_menu h3::after {
        width: 38px;
    }

    .right_menu pre {
        font-size: 13px;
        line-height: 1.5;
        padding: 12px;
        border-radius: 6px;
    }


    
    .web-title {
        font-size: 1.8rem;
    }
    
    .web-info {
        font-size: 13px;
    }

    .sub-items {
        gap: 1rem;
    }
    .one-sub-item {
        flex: 0 1 calc(50% - 1rem);
        min-width: auto;
        padding: 1.5rem 0.8rem;
    }
    .one-sub-item .num {
        font-size: 2rem;
    }
    .one-sub-item .text {
        font-size: 0.95rem;
    }

     .right_downloads {
        padding: 16px;
        border-radius: 10px;
    }

    .right_downloads h3 {
        font-size: 12px;
        margin-bottom: 14px;
    }

    .right_downloads h3::after {
        width: 45px;
        height: 2.5px;
    }

    .right_downloads .download-box {
        flex-direction: column;
        align-items: center;
        gap: 12px;
    }

    .right_downloads .download-box .btn {
        width: 100%;
        max-width: 260px;
        font-size: 1rem;
        padding: 11px 18px;
    }




}

@media (max-width: 576px) {

    .zl_title
    {
        font-size:1.1em;
    }
.download-modal .pc-link p
{
    font-size:12px;
}
.download-modal .btn-pc-download
{
    font-size:12px;
}
    .nava
    {
        font-size:12px;
    }
    .big-title h1
    {
        font-size:1.25rem;
    }
    .big_info .infos
    {
        display:block;
    }

    body, .screen-1 a, .screen-3 .navbar, .screen-5 .section-title  {
        font-size: 18px;
    }
.screen-1 a
{
    font-size:12px;
}

    #back-to-top {
        width: 40px;
        height: 40px;
        right: 12px;
        bottom: 16px;
        font-size: 1.1rem;
    }

    
    .footer 
    {
        font-size:12px;
    }
    .screen-3-5 .nav-tabs .nav-link {
        font-size: 12px;
        padding: 6px 10px;
    }

    .right_menu h3 {
            font-size: 1.1rem;
        }

    .right_menu pre {
        font-size: 12px;
        padding: 10px;
        line-height:1.5;
    }

    .relation_box .relation-tab-btn {
        flex: 1;
        min-width: 70px;
        font-size: 0.8rem;
        padding: 6px 8px;
    }

    .left_item_box h3 {
        font-size: 0.95rem;
    }

    .left_item_box ul li {
        font-size: 0.9rem;
    }

    
    .relation_box .relation-link-list a {
        font-size: 0.875rem;
    }

     .web-title {
        font-size: 1.6rem;
    }
    
    .web-info {
        font-size: 12px;
    }

     .one-sub-item {
        padding: 1.3rem 0.6rem;
    }
    .one-sub-item .num {
        font-size: 1.8rem;
    }
    .one-sub-item .text {
        font-size: 0.9rem;
    }

    .download-modal .modal-content {
        padding: 20px;
        max-width: 300px;
    }
    .download-modal .qrcode img {
        width: 160px;
        height: 160px;
    }
    .download-modal h4 {
        font-size: 13px;
    }

     .right_downloads h3 {
        font-size: 12px;
    }

    .right_downloads .download-box .btn {
        font-size: 0.95rem;
        padding: 10px 16px;
    }


    .right_big_box
    {
        border:none;
    }
    .hover-tabs-nav {
        gap: 4px;
        padding: 0.5rem;
    }
    .tab-btn {
        padding: 0.2rem 0.5rem 0.2rem 0px;
        font-size: 13px;
    }

    .hover-tabs-nav .tab-name
    {
        width:100%;
        display:block;
        
    }

    .big_info h2 {
        font-size: 1.15rem;
    }

    .big_info .infos {
        font-size: 0.875rem;
    }

    .big_info .infos a {
        font-size: 0.85rem;
        padding: 3px 7px;
    }


}