/* 内容区域显示控制 */
.content-section {
    display: none;
}
.content-section.active {
    display: block;
}

/* 防止表格中的标签文本换行 */
.payment-table .label {
    white-space: nowrap;
}

/* 去掉链接的下划线 */
.link {
    text-decoration: none;
}

/* 确保页脚始终在底部 */
body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    margin: 0;
}

.content-wrapper {
    flex: 1;
}

/* 重要日期的紫色加粗样式 */
.date-highlight {
    color: #301f81;
    font-weight: bold;
}
/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
    min-height: 100vh;
}

main .container {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 15px;
}

/* 媒体查询应从小到大排序 */
@media (min-width: 768px) {
    main .container {
        width: 750px;
    }
}
@media (min-width: 992px) {
    main .container {
        width: 970px;
    }
}
@media (min-width: 1200px) {
    main .container {
        width: 1170px;
    }
}

h2 {
    font-size: 24px;
    margin-bottom: 20px;
    color: #301f81;
}

ul {
    list-style-type: none;
    padding-left: 20px;
}

li {
    margin-bottom: 8px;
    position: relative;
}

li:before {
    content: "•";
    position: absolute;
    left: -15px;
    color: #333;
}

/* 横幅样式 */
.banner {
    margin: 0;
    padding: 0;
    overflow: hidden;
    line-height: 0;
    font-size: 0;
    position: relative;
}

.banner-image {
    width: 100%;
    height: auto;
    display: block;
    object-fit: cover;
}

.banner-content {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 2;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100%;
}

.banner-text {
    width: 100%;
    text-align: center;
}

.banner h1 {
    font-size: 48px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.large-number {
    font-size: 120px;
    font-weight: bold;
    line-height: 0.8;
}

.th {
    font-size: 40px;
    align-self: flex-start;
}

.bics-title {
    font-size: 70px;
    margin-left: 15px;
}

.banner h2 {
    font-size: 36px;
    margin-bottom: 30px;
    color: white;
}

.banner h3 {
    font-size: 30px;
    margin-bottom: 15px;
}

.banner-info {
    font-size: 20px;
    margin-bottom: 10px;
}

/* 小横幅样式 */
.banner-small {
    padding: 25px 0 20px;
}

.banner-small h3 {
    font-size: 26px;
    margin-bottom: 10px;
}

.banner-small .banner-info {
    font-size: 18px;
    margin-bottom: 8px;
}

/* 导航菜单样式 */
.main-nav {
    background-color: #d9d6d6;
    padding: 0;
    border-bottom: 1px solid #ccc;
    position: sticky;
    top: 0;
    z-index: 100;
}

/* 导航标题栏样式 - 显示当前页面标题和汉堡菜单按钮的区域 */
.nav-header {
    background-color: #d9d6d6;
    padding: 0 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

/* 当前页面标题样式 */
.current-page-title {
    color: #301f81;
    font-size: 18px;
    font-weight: bold;
}

/* 汉堡菜单按钮样式 */
.menu-toggle {
    cursor: pointer;
    padding: 15px;
    display: block;
}

.menu-toggle .bar {
    width: 25px;
    height: 3px;
    background-color: #301f81;
    margin: 5px auto;
    display: block;
    transition: all 0.3s ease;
}

.main-nav ul {
    display: flex;
    justify-content: center;
    padding: 0;
    margin: 0;
    transition: max-height 0.3s ease;
    background-color: #d9d6d6;
}

.main-nav li {
    margin: 0;
}

.main-nav li:before {
    display: none;
}

.main-nav a {
    color: #301f81;
    text-decoration: none;
    font-size: 16px;
    padding: 15px 50px;
    display: block;
    transition: all 0.3s ease;
    border-right: 1px solid rgba(255, 255, 255, 0.1);
    font-weight: 700;
}

p strong {
    color: red;
    font-weight: 700;
}

.link {
    color: #301f81;
    font-weight: 700;
}

.main-nav a:hover,
.main-nav a.active {
    background-color: #301f81;
    color: white;
}

/* 汉堡菜单动画 */
.menu-toggle.active .bar:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.menu-toggle.active .bar:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active .bar:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* 大屏幕样式 */
@media (min-width: 769px) {
    /* 在大屏幕上隐藏导航标题栏 */
    .nav-header {
        display: none;
    }
    
    .main-nav ul {
        flex-direction: row;
    }
    
    .main-nav li {
        width: auto;
    }
}

/* 小屏幕样式 */
@media (max-width: 768px) {
    .main-nav .container {
        position: relative;
        padding: 0;
    }
    
    .main-nav ul {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        max-height: 0;
        overflow: hidden;
        width: 100%;
        z-index: 1000;
    }
    
    .main-nav ul.active {
        max-height: 500px;
    }
    
    .main-nav li {
        width: 100%;
    }
    
    .main-nav a {
        padding: 15px 20px;
        border-right: none;
        border-bottom: 1px solid rgba(0, 0, 0, 0.1);
        text-align: center;
    }
}

/* 主要内容样式 */
main {
    padding: 0;
    background-color: #fff;
}

.content-wrapper {
    background-color: #fff;
    background-image: url('content-bg.jpg');
    background-position: center top;
    background-repeat: no-repeat;
    padding: 20px 0;
}

section {
    margin-bottom: 30px;
    padding: 20px 0;
}

/* 页面部分样式 */
main > div[id] {
    padding-top: 40px;
    margin-bottom: 40px;
}

main > div[id]:not(:first-child) {
    border-top: 1px solid #eee;
}

main > div[id] > section:first-child h2 {
    font-size: 26px;
    color: #2b286f;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid #ddd;
}

/* 介绍部分样式 */
.intro-section {
    display: flex;
    gap: 40px;
    background-color: rgba(255, 255, 255, 0.2);
    padding: 80px 40px 80px 40px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    position: relative;
    z-index: 1;
    overflow: hidden;
    max-width: 1100px;
    border-radius: 8px;
}

.intro-section::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('https://bics-ai-org-1257115555.cos.ap-hongkong.myqcloud.com/assets/4.png') no-repeat center center;
    background-size: cover;
    opacity: 0.9;
    z-index: -2;
}

.intro-section::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(64, 83, 169, 0.7);
    z-index: -1;
}


.intro-box {
    flex: 1;
    background-color: rgba(255, 255, 255, 0.92);
    padding: 30px;
    border-radius: 5px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

.intro-box h2 {
    font-size: 24px;
    margin-bottom: 20px;
    color: #301f81;
    font-weight: bold;
    text-align: center;
}

.intro-box p {
    font-size: 16px;
    margin-bottom: 15px;
    line-height: 1.8;
    color: #333;
}

@media (max-width: 768px) {
    .intro-section {
        background-color: #fff;
        padding: 25px;
        border: 1px solid #ddd;
        margin-top: 20px;
        box-shadow: 0 2px 5px rgba(0,0,0,0.05);    
        padding: 0px;
    }

    .intro-section::before {
        background: none;
    }

    .intro-section::after {
        background: none;
    }
    .intro-box {
        flex: 2;
        margin-bottom: 0px;
    }
}

.campus-img {
    flex: 1;
    background: url('campus.jpg') no-repeat center center;
    background-size: cover;
    min-height: 250px;
}

/* 主题部分样式 */
.topics-container {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.topics-row {
    display: flex;
    gap: 30px;
}

.topic-column {
    flex: 1;
    min-width: 250px;
}

.topic-column h3 {
    font-size: 18px;
    margin-bottom: 15px;
    color: #301f81;
    font-weight: bold;
}

.topic-column ul {
    padding-left: 20px;
}

.topic-column li {
    font-size: 16px;
    margin-bottom: 8px;
}

.topics-section h2, 
.keynote-section h2, 
.dates-section h2, 
.contact-section h2,
.program-section h2,
.registration-section h2 {
    font-size: 22px;
    margin-bottom: 20px;
    color: #301f81;
    font-weight: bold;
}

/* 日期部分样式 */
.dates-section ul {
    padding-left: 25px;
}

.dates-section li {
    font-size: 16px;
    margin-bottom: 10px;
}

/* 联系部分样式 */
.contact-section p {
    font-size: 16px;
}

/* 委员会页面样式 */
.committee-section {
    padding: 15px 20px;
}

.committee-section h3 {
    color: #4B0082;
    font-size: 18px;
    margin: 20px 0 10px;
    font-weight: bold;
}

.committee-section h3:first-child {
    margin-top: 0;
}

.committee-member {
    margin-bottom: 5px;
    font-size: 16px;
    padding-left: 0;
}

.committee-member span {
    font-size: 15px;
    color: #666;
}

/* 页脚样式 */
footer {
    background-color: #2b286f;
    color: white;
    padding: 15px 0;
    text-align: center;
    font-size: 14px;
}

/* 下载部分样式 */
.download-section {
    text-align: right;
    margin: 15px 0;
}

.download-btn {
    display: inline-block;
    background-color: #2a75b3;
    color: white;
    padding: 10px 20px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: bold;
    font-size: 14px;
    transition: background-color 0.3s ease;
}

.download-btn:hover {
    background-color: #1c5a8b;
}

/* 程序和注册部分 */
.program-section {
    min-height: 150px;
    padding: 30px;
    background-color: #f9f9f9;
    border: 1px solid #eee;
    text-align: center;
}

.program-section p {
    font-size: 16px;
    font-style: italic;
    color: #666;
}

.registration-section p {
    font-size: 16px;
    font-style: italic;
    color: #666;
    text-align: center;
}

/* 注册页面样式 */
.registration-section {
    min-height: 150px;
    padding: 20px;
    background-color: #fff;
    border: 1px solid #eee;
    text-align: left;
}

.registration-section h2 {
    color: #301f81;
    font-size: 24px;
    font-weight: bold;
    text-align: center;
    margin-bottom: 30px;
}

.registration-content {
    max-width: 900px;
    margin: 0 auto;
    line-height: 1.8;
}

.registration-content p {
    margin-bottom: 15px;
    font-size: 16px;
}

.registration-fees {
    margin: 20px 0;
}

.payment-info {
    margin: 30px 0;
}

.payment-table {
    margin: 15px 0;
    border-collapse: collapse;
    width: 100%;
    max-width: 600px;
}

.payment-table td {
    padding: 5px;
    font-size: 16px;
}

.payment-table .label {
    width: 120px;
    text-align: right;
    font-weight: bold;
}

.international-payment {
    margin: 15px 0;
}

.international-payment p {
    margin-bottom: 8px;
}

.registration-notes {
    margin-top: 30px;
    border-top: 1px solid #eee;
    padding-top: 20px;
}

/* 响应式设计 */
@media (max-width: 1200px) {
    .large-number {
        font-size: 100px;
    }
    
    .bics-title {
        font-size: 60px;
    }
    
    .banner h2 {
        font-size: 32px;
    }
}

@media (max-width: 992px) {
    .intro-section {
        flex-direction: column;
    }
    
    .campus-img {
        min-height: 300px;
    }
    
    .topics-row {
        flex-direction: column;
    }
    
    .large-number {
        font-size: 80px;
    }
    
    .bics-title {
        font-size: 50px;
    }
    
    .th {
        font-size: 32px;
    }
    
    .banner h2 {
        font-size: 28px;
    }
    
    .banner h3 {
        font-size: 24px;
    }
}

@media (max-width: 768px) {
    .banner h1 {
        font-size: 36px;
    }
    
    .large-number {
        font-size: 70px;
    }
    
    .bics-title {
        font-size: 42px;
    }
    
    .banner h2 {
        font-size: 24px;
    }
    
    .current-page-title {
        display: block;
    }
}

/* 固定在右下角的下载按钮 */
.fixed-download-btn {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 99;
}

.fixed-download-btn .download-btn {
    display: inline-block;
    background-color: #2a75b3;
    color: white;
    padding: 12px 24px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: bold;
    font-size: 16px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
}

/* 响应式设计中的下载按钮 */
@media (max-width: 768px) {
    .fixed-download-btn {
        bottom: 20px;
        right: 20px;
    }
    
    .fixed-download-btn .download-btn {
        padding: 10px 18px;
        font-size: 14px;
    }
}

.fixed-download-btn .download-btn:hover {
    background-color: #1c5a8b;
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
    transform: translateY(-2px);
}

.committee-member {
    font-weight: 700;
}
.committee-member span {
    font-weight: 400;
}