/* 公共样式 - 会议网站 */
@charset "utf-8";

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-family: "Microsoft YaHei", "微软雅黑", -apple-system, BlinkMacSystemFont, sans-serif;
    font-size: 16px;
}

body {
    margin: 0;
    padding: 0;
    background: url('../images/bg.jpg') no-repeat center center fixed;
    background-size: cover;
    color: #333;
    line-height: 1.6;
    padding-top: 56px;
}

a {
    text-decoration: none;
    color: inherit;
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    border: 0;
}

/* 容器 */
.wrap {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 清除浮动 */
.clearfix::after {
    content: "";
    display: table;
    clear: both;
}

/* ========== 头部区域 ========== */
.header-wrap {
    width: 100%;
}

/* 导航栏 - 固定顶部 */
.nav {
    background: #1a365d;
    width: 100%;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
}

/* Banner 横幅 - 固定顶部导航下方 */
.banner {
    width: 100%;
    background: #0f2744;
}

.banner img {
    display: block;
    width: 100%;
    object-fit: cover;
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.nav ul {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    margin: 0;
    padding: 0;
    list-style: none;
}

.nav li {
    position: relative;
}

.nav li a {
    display: block;
    padding: 18px 25px;
    color: #fff;
    font-size: 16px;
    transition: background 0.3s;
    white-space: nowrap;
    text-align: center;
}

.nav li a:hover,
.nav li .newslist_active {
    background: #2c5282;
}

.nav .second-level {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: #1a365d;
    min-width: 180px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.15);
    z-index: 100;
}

.nav li:hover .second-level {
    display: block;
}

.nav .second-level li a {
    padding: 12px 20px;
    font-size: 14px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.nav .second-level li a:hover {
    background: #2c5282;
}

/* 移动端菜单按钮 */
.nav-toggle {
    display: none;
    position: absolute;
    top: 10px;
    right: 15px;
    width: 44px;
    height: 44px;
    background: rgba(255,255,255,0.1);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    z-index: 1001;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 3px;
    background: #fff;
    margin: 8px auto;
    transition: all 0.3s;
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* ========== 主内容区 ========== */
.main {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

.main.full {
    max-width: 100%;
    padding: 0;
}

/* 页面标题区 */
.page-header {
    background: linear-gradient(135deg, #1a365d 0%, #2c5282 100%);
    padding: 60px 20px;
    text-align: center;
    color: #fff;
}

.page-header h1 {
    font-size: 32px;
    margin-bottom: 10px;
    letter-spacing: 3px;
}

.page-header p {
    font-size: 16px;
    color: #90cdf4;
}

/* 内容卡片 */
.card {
    background: #fff;
    border-radius: 8px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.card h2 {
    font-size: 22px;
    color: #1a365d;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 3px solid #2c5282;
}

.card h3 {
    font-size: 18px;
    color: #2c5282;
    margin: 20px 0 10px;
}

.card p {
    margin-bottom: 15px;
    line-height: 1.8;
    color: #555;
}

.card ul {
    margin: 15px 0;
    padding-left: 20px;
}

.card ul li {
    margin-bottom: 10px;
    line-height: 1.8;
    list-style: disc;
}

.register-cta {
    text-align: center;
    padding: 40px 20px;
}

.btn-register {
    display: inline-block;
    padding: 16px 48px;
    background: linear-gradient(135deg, #e53e3e, #c53030);
    color: #fff;
    font-size: 18px;
    font-weight: bold;
    border-radius: 50px;
    text-decoration: none;
    transition: all 0.3s;
    box-shadow: 0 4px 15px rgba(197, 48, 48, 0.4);
}

.btn-register:hover {
    background: linear-gradient(135deg, #c53030, #9b2c2c);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(197, 48, 48, 0.5);
}

/* 重要日期 */
.dates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.date-item {
    background: linear-gradient(135deg, #1a365d 0%, #2c5282 100%);
    color: #fff;
    padding: 20px;
    border-radius: 8px;
    text-align: center;
}

.date-item .label {
    font-size: 14px;
    color: #90cdf4;
    margin-bottom: 8px;
}

.date-item .value {
    font-size: 18px;
    font-weight: bold;
}

/* 图片展示 */
.image-section {
    margin: 20px 0;
}

.image-section img {
    width: 100%;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

/* 快捷入口 */
.quick-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.quick-link {
    display: block;
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
}

.quick-link:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

.quick-link img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.quick-link .info {
    padding: 20px;
}

.quick-link .info h3 {
    font-size: 18px;
    color: #1a365d;
    margin-bottom: 8px;
}

.quick-link .info p {
    font-size: 14px;
    color: #888;
    margin: 0;
}

/* 主办单位 */
.org-list {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin: 20px 0;
}

.org-list span {
    background: #edf2f7;
    padding: 10px 20px;
    border-radius: 25px;
    font-size: 14px;
    color: #4a5568;
}

/* 分会场 */
.topic-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.topic-item {
    background: #fff;
    border-radius: 8px;
    padding: 25px;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    border-left: 4px solid #2c5282;
}

.topic-item h3 {
    color: #1a365d;
    margin-bottom: 10px;
}

.topic-item p {
    color: #666;
    font-size: 14px;
    margin: 0;
}

/* 联系方式 */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.contact-item {
    background: #fff;
    padding: 25px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.contact-item .label {
    font-size: 14px;
    color: #888;
    margin-bottom: 8px;
}

.contact-item .value {
    font-size: 16px;
    color: #1a365d;
    font-weight: bold;
}

/* 按钮 */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    font-size: 16px;
    transition: all 0.3s;
    cursor: pointer;
}

.btn-primary {
    background: #2c5282;
    color: #fff;
}

.btn-primary:hover {
    background: #1a365d;
}

.btn-green {
    background: #27B148;
    color: #fff;
}

.btn-green:hover {
    background: #1e8449;
}

.btn-download {
    background: #27B148;
    color: #fff;
    padding: 15px 40px;
    border-radius: 8px;
    font-size: 16px;
    display: inline-block;
    margin: 20px 0;
}

.btn-download:hover {
    background: #1e8449;
}

/* 海报展示 */
.poster-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #e2e8f0;
}

.poster-tab {
    padding: 12px 20px;
    border: 2px solid #e2e8f0;
    background: #fff;
    color: #4a5568;
    border-radius: 30px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s;
}

.poster-tab:hover {
    border-color: #2c5282;
    color: #2c5282;
}

.poster-tab.active {
    background: linear-gradient(135deg, #1a365d 0%, #2c5282 100%);
    color: #fff;
    border-color: #1a365d;
}

.poster-content {
    min-height: 400px;
}

.poster-panel {
    display: none;
}

.poster-panel.active {
    display: block;
}

.poster-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 15px;
}

.poster-item {
    background: #f8fafc;
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
}

.poster-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.poster-item img {
    width: 100%;
    height: 280px;
    object-fit: contain;
    background: #f1f5f9;
}

/* 历届合影图库 */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin: 20px 0;
}

.gallery-item {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s, box-shadow 0.3s;
}

.gallery-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.15);
}

.gallery-item a {
    display: block;
    position: relative;
    overflow: hidden;
}

.gallery-item img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    object-position: center top;
    transition: transform 0.3s;
}

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

.gallery-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s;
}

.gallery-item:hover .gallery-overlay {
    opacity: 1;
}

.icon-zoom {
    width: 50px;
    height: 50px;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="white"><path d="M15.5 14h-.79l-.28-.27A6.471 6.471 0 0 0 16 9.5 6.5 6.5 0 1 0 9.5 16c1.61 0 3.09-.59 4.23-1.57l.27.28v.79l5 4.99L20.49 19l-4.99-5zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"/></svg>') no-repeat center;
    background-size: contain;
}

.gallery-item .title {
    padding: 15px 15px 5px;
    font-size: 15px;
    font-weight: 600;
    color: #1a365d;
}

.gallery-item .subtitle {
    padding: 0 15px 15px;
    font-size: 13px;
    color: #718096;
}

/* 图片预览弹窗 */
.lightbox-modal {
    display: none;
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.92);
    align-items: center;
    justify-content: center;
}

.lightbox-modal.show {
    display: flex;
}

.lightbox-content {
    max-width: 90%;
    max-height: 85vh;
    object-fit: contain;
    box-shadow: 0 0 30px rgba(0,0,0,0.5);
    animation: lightboxZoom 0.3s;
}

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

.lightbox-close {
    position: absolute;
    top: 20px;
    right: 30px;
    color: #fff;
    font-size: 40px;
    font-weight: bold;
    cursor: pointer;
    transition: color 0.3s;
    z-index: 10000;
}

.lightbox-close:hover {
    color: #90cdf4;
}

.lightbox-caption {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    color: #fff;
    font-size: 16px;
    padding: 10px 25px;
    background: rgba(0,0,0,0.6);
    border-radius: 25px;
}

/* 响应式 */
@media (max-width: 768px) {
    .poster-tabs {
        flex-direction: column;
    }
    
    .poster-tab {
        width: 100%;
        text-align: center;
    }
    
    .poster-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }
    
    .poster-item img {
        height: 180px;
    }
    
    .gallery-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .gallery-item img {
        height: 200px;
    }
}

@media (max-width: 480px) {
    .poster-grid {
        grid-template-columns: 1fr;
    }
}

/* 页脚 */
.footer-box {
    background: #1a365d;
    color: #fff;
    margin-top: 60px;
}

.footer {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
}

.footer-section {
    flex: 1;
    min-width: 200px;
}

.footer-section h4 {
    color: #fff;
    margin-bottom: 12px;
    font-size: 16px;
}

.footer-section p {
    margin: 6px 0;
    font-size: 14px;
    color: #cbd5e0;
}

.footer .contacts span {
    display: block;
    margin-bottom: 10px;
    line-height: 1.8;
}

.copyright {
    background: #0f2744;
    padding: 20px;
    text-align: center;
    font-size: 14px;
    color: #a0aec0;
}

.copyright a {
    color: #a0aec0;
}

.copyright a:hover {
    color: #fff;
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    /* 导航栏移动端 */
    .nav-toggle {
        display: block;
        position: fixed;
        top: 10px;
        right: 15px;
    }

    .nav-inner {
        position: relative;
        padding-right: 60px;
    }

    .nav ul {
        display: none;
        flex-direction: column;
        width: 100%;
        position: fixed;
        top: 56px;
        left: 0;
        background: #1a365d;
        box-shadow: 0 4px 15px rgba(0,0,0,0.2);
        z-index: 999;
        max-height: calc(100vh - 56px);
        overflow-y: auto;
    }

    .nav ul.active {
        display: flex;
    }

    .nav li a {
        padding: 15px 20px;
        border-bottom: 1px solid rgba(255,255,255,0.1);
        text-align: left;
    }

    .nav .second-level {
        position: static;
        box-shadow: none;
        background: rgba(0,0,0,0.2);
    }

    .nav .second-level li a {
        padding-left: 40px;
    }

    .page-header {
        padding: 40px 20px;
        margin-top: 56px;
    }

    .page-header h1 {
        font-size: 24px;
    }

    .card {
        padding: 20px;
    }

    .dates-grid,
    .quick-links,
    .topic-list,
    .contact-grid,
    .gallery-grid {
        grid-template-columns: 1fr;
    }

    .banner img {
        max-height: 200px;
    }
}