/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #1d1d1f;
    background: #000;
    overflow-x: hidden;
}

/* Navigation */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(20px);
    z-index: 1000;
    padding: 20px 0;
    transition: all 0.3s ease;
}

nav.scrolled {
    background: rgba(0, 0, 0, 0.95);
    padding: 15px 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
}

.logo {
    font-size: 24px;
    font-weight: 600;
    color: #fff;
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    color: #fff;
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: #007aff;
}

/* 语言切换器样式 */
.language-switcher {
    display: flex;
    gap: 0.5rem;
    margin-left: 2rem;
}

.lang-btn {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: #fff;
    padding: 0.4rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 0.5px;
}

.lang-btn:hover {
    border-color: #007aff;
    background: rgba(0, 122, 255, 0.1);
    color: #007aff;
}

.lang-btn.active {
    background: #007aff;
    border-color: #007aff;
    color: #fff;
}

.lang-btn.active:hover {
    background: #0056b3;
    border-color: #0056b3;
}

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(135deg, #000 0%, #1a1a1a 100%);
    position: relative;
    overflow: hidden;
}

.hero-content {
    max-width: 800px;
    padding: 0 40px;
    z-index: 2;
}

.hero h1 {
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: 700;
    color: #fff;
    margin-bottom: 20px;
    line-height: 1.1;
    opacity: 0;
    transform: translateY(50px);
    animation: fadeInUp 1s ease 0.5s forwards;
}

.hero .subtitle {
    font-size: clamp(1.2rem, 3vw, 1.8rem);
    color: #a1a1a6;
    margin-bottom: 40px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s ease 0.8s forwards;
}

.cta-button {
    display: inline-block;
    padding: 16px 32px;
    background: #007aff;
    color: #fff;
    text-decoration: none;
    border-radius: 50px;
    font-size: 18px;
    font-weight: 500;
    transition: all 0.3s ease;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s ease 1.1s forwards;
}

.cta-button:hover {
    background: #0056cc;
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 122, 255, 0.3);
}

/* Video Section */
.video-section {
    position: relative;
    background: #000;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 上方文字容器 */
.video-text-container {
    position: sticky;
    top: 0;
    width: 100%;
    height: 30vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 60px;
    z-index: 10;
}

/* 下方视频容器 */
.video-container {
    position: sticky;
    top: 22vh;
    width: 100%;
    height: 75vh;
    overflow: hidden;
    z-index: 5;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 60px;
}

.video-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 75%;
    height: 85%;
    border-radius: 20px;
    opacity: 0;
    transition: opacity 0.8s ease;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.video-content.active {
    opacity: 1;
}

.video-content video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 20px;
}

.video-text-content {
    position: absolute;
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
    width: 100%;
    max-width: 800px;
    text-align: center;
    margin-top: 60px;
}

.video-text-content.active {
    opacity: 1;
    transform: translateY(0);
}

.text-content {
    color: #fff;
}

.video-number {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: #007aff;
    margin-bottom: 15px;
    letter-spacing: 2px;
}

.video-text-content h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: 15px;
    line-height: 1.2;
    color: #fff;
}

.video-text-content p {
    font-size: clamp(1rem, 1.5vw, 1.2rem);
    color: #a1a1a6;
    line-height: 1.5;
    margin-bottom: 0;
}

/* Trigger Section */
.trigger-section {
    height: 400vh;
    position: relative;
}



/* Activities Section */
.activities {
    background: #f5f5f7;
    padding: 120px 0;
    position: relative;
}

.activities-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 40px;
}

.activities-title {
    text-align: center;
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 700;
    margin-bottom: 20px;
    color: #1d1d1f;
}

.activities-subtitle {
    text-align: center;
    font-size: clamp(1.1rem, 2vw, 1.3rem);
    color: #86868b;
    margin-bottom: 80px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 3px;
    height: 100%;
    background: linear-gradient(to bottom, #007aff, #5ac8fa);
    border-radius: 2px;
}

.timeline-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 60px;
    position: relative;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-date {
    width: 45%;
    text-align: center;
    position: relative;
}

.timeline-item:nth-child(odd) .timeline-date {
    text-align: right;
    padding-right: 30px;
}

.timeline-item:nth-child(even) .timeline-date {
    text-align: left;
    padding-left: 30px;
}

.date-text {
    display: inline-block;
    background: #007aff;
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.timeline-content {
    width: 45%;
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    position: relative;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.timeline-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.timeline-icon {
    font-size: 24px;
    margin-bottom: 15px;
    display: inline-block;
}

.timeline-content h3 {
    font-size: 20px;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 15px;
    line-height: 1.3;
}

.timeline-content p {
    color: #86868b;
    font-size: 16px;
    line-height: 1.6;
    margin: 0;
}

/* Timeline连接点 */
.timeline-item::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 12px;
    height: 12px;
    background: #007aff;
    border: 3px solid white;
    border-radius: 50%;
    z-index: 2;
    box-shadow: 0 2px 10px rgba(0, 122, 255, 0.3);
}

/* Team Section */
/* 黑色背景版本 */
.team {
    background: #000;
    padding: 120px 0;
    position: relative;
    overflow: hidden;
}

/* 白色背景版本 - 如需使用，请取消注释并注释掉黑色版本 */
/*
.team {
    background: #fff;
    padding: 120px 0;
    position: relative;
    overflow: hidden;
}

.team::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 20%, rgba(0, 0, 0, 0.05) 0%, transparent 50%);
    pointer-events: none;
}

.team-title {
    color: #1d1d1f;
    text-shadow: none;
}

.team-subtitle {
    color: #86868b;
    text-shadow: none;
}

.member-name {
    color: #1d1d1f;
    text-shadow: none;
}

.member-role {
    color: #007aff;
}

.member-description {
    color: #86868b;
}

.logo-text {
    color: #1d1d1f;
}

.credits-text {
    color: #86868b;
}

.institution-name {
    color: #1d1d1f;
}

.institution-desc {
    color: #86868b;
}

.team::after {
    color: rgba(0, 0, 0, 0.05);
}

.team-container::before {
    color: rgba(0, 0, 0, 0.05);
}

.team-container::after {
    color: rgba(0, 0, 0, 0.05);
}

.avatar-placeholder {
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.team-member:hover .avatar-placeholder {
    box-shadow: 0 12px 35px rgba(0, 0, 0, 0.2);
}

.avatar-placeholder::after {
    background: rgba(0, 0, 0, 0.1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.institution-logo {
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.1) 0%, rgba(0, 0, 0, 0.05) 100%);
    border: 2px solid rgba(0, 0, 0, 0.1);
}

.logo-symbol {
    color: #1d1d1f;
}

.team-footer {
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}
*/

.team::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 20%, rgba(255, 255, 255, 0.05) 0%, transparent 50%);
    pointer-events: none;
}

.team-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
    position: relative;
    z-index: 2;
}

.team-header {
    text-align: center;
    margin-bottom: 80px;
}

.team-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 40px;
    gap: 20px;
}

.logo-shapes {
    display: flex;
    gap: 8px;
}

.shape {
    border-radius: 50%;
    width: 12px;
    height: 12px;
}

.shape-1 {
    background: #ffeaa7;
}

.shape-2 {
    background: #a29bfe;
}

.shape-3 {
    background: #fd79a8;
}

.logo-text {
    font-size: 18px;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.9);
    margin-left: 20px;
    position: relative;
}

.logo-text::before {
    content: '|';
    position: absolute;
    left: -15px;
    color: rgba(255, 255, 255, 0.5);
}

.team-title {
    text-align: center;
    font-size: clamp(3rem, 6vw, 4rem);
    font-weight: 700;
    margin-bottom: 20px;
    color: #fff;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.team-subtitle {
    text-align: center;
    font-size: clamp(1.2rem, 2.5vw, 1.5rem);
    color: rgba(255, 255, 255, 0.8);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    text-shadow: 0 1px 5px rgba(0, 0, 0, 0.3);
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 50px;
    margin-top: 60px;
    justify-items: center;
}

.team-member {
    text-align: center;
    transition: all 0.4s ease;
    cursor: pointer;
}

.team-member:hover {
    transform: translateY(-15px) scale(1.05);
}

.member-avatar {
    margin-bottom: 20px;
    position: relative;
}

.avatar-placeholder {
    width: 120px;
    height: 120px;
    margin: 0 auto;
    border-radius: 50%;
    position: relative;
    transition: all 0.3s ease;
    box-shadow: 0 8px 25px rgba(255, 255, 255, 0.1);
    overflow: hidden;
    background: #333;
}

.avatar-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    transition: transform 0.3s ease;
}

/* 为每个成员创建不同的旋转效果 */
.team-member:nth-child(1) .avatar-placeholder {
    transform: rotate(-3deg);
}

.team-member:nth-child(2) .avatar-placeholder {
    transform: rotate(2deg);
}

.team-member:nth-child(3) .avatar-placeholder {
    transform: rotate(-2deg);
}

.team-member:nth-child(4) .avatar-placeholder {
    transform: rotate(1deg);
}

.team-member:hover .avatar-placeholder {
    transform: rotate(0deg) scale(1.1);
    box-shadow: 0 12px 35px rgba(255, 255, 255, 0.2);
}

.team-member:hover .avatar-image {
    transform: scale(1.05);
}

/* 添加装饰性元素 */
.avatar-placeholder::after {
    content: '';
    position: absolute;
    top: -5px;
    right: -5px;
    width: 20px;
    height: 20px;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.member-name {
    font-size: 20px;
    font-weight: 600;
    color: #fff;
    margin-bottom: 5px;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.member-role {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 400;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.member-description {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.4;
    max-width: 180px;
    margin: 0 auto;
}

/* 添加一些装饰性的浮动元素 */
.team::after {
    content: '●';
    position: absolute;
    top: 15%;
    left: 10%;
    color: rgba(255, 255, 255, 0.05);
    font-size: 30px;
    animation: float 6s ease-in-out infinite;
}

.team-container::before {
    content: '▲';
    position: absolute;
    top: 20%;
    right: 15%;
    color: rgba(255, 255, 255, 0.05);
    font-size: 25px;
    animation: float 8s ease-in-out infinite reverse;
}

.team-container::after {
    content: '■';
    position: absolute;
    bottom: 20%;
    left: 20%;
    color: rgba(255, 255, 255, 0.05);
    font-size: 20px;
    animation: float 7s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-20px);
    }
}

/* Team Footer */
.team-footer {
    margin-top: 80px;
    padding-top: 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.2);
    text-align: center;
}

.team-credits {
    margin-bottom: 40px;
}

.credits-text {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.8);
    font-style: italic;
}

.team-institution {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 25px;
}

.institution-logo {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.2) 0%, rgba(255, 255, 255, 0.1) 100%);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.logo-symbol {
    font-size: 12px;
    font-weight: 700;
    color: #fff;
    letter-spacing: 1px;
}

.institution-text {
    text-align: left;
}

.institution-name {
    font-size: 20px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 5px;
}

.institution-desc {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.7);
}

/* Footer */
footer {
    background: #1d1d1f;
    color: #a1a1a6;
    padding: 60px 0 40px;
    text-align: center;
}

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

.footer-links {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.footer-links a {
    color: #a1a1a6;
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #fff;
}

.copyright {
    font-size: 14px;
    color: #86868b;
}

/* Animations */
@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scroll Indicator */
.scroll-indicator {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    color: #fff;
    font-size: 14px;
    opacity: 0.7;
    animation: bounce 2s infinite;
    z-index: 1000;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0) translateX(-50%);
    }
    40% {
        transform: translateY(-10px) translateX(-50%);
    }
    60% {
        transform: translateY(-5px) translateX(-50%);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 20px;
    }

    .nav-links {
        display: none;
    }
    
    .language-switcher {
        margin-left: 1rem;
        gap: 0.3rem;
    }
    
    .lang-btn {
        padding: 0.3rem 0.6rem;
        font-size: 0.7rem;
    }

    .hero-content {
        padding: 0 20px;
    }

    /* 视频区域移动端样式 */
    .video-text-container {
        height: 35vh;
        padding: 20px 20px;
    }
    
    .video-container {
        top: 33vh;
        height: 67vh;
    }
    
    .video-content {
        width: 90%;
        height: 85%;
        border-radius: 15px;
        box-shadow: 0 15px 40px rgba(0, 0, 0, 0.4);
    }
    
    .video-content video {
        border-radius: 15px;
    }
    
    .video-text-content {
        max-width: 100%;
    }
    
    .video-text-content h2 {
        font-size: clamp(1.8rem, 6vw, 2.2rem);
        margin-bottom: 15px;
    }
    
    .video-text-content p {
        font-size: clamp(0.9rem, 3vw, 1rem);
        line-height: 1.4;
    }
    
    .video-number {
        font-size: 12px;
        margin-bottom: 10px;
    }



    /* Activities 移动端样式 */
    .activities-container {
        padding: 0 20px;
    }

    .timeline::before {
        left: 30px;
        transform: none;
    }

    .timeline-item {
        flex-direction: column;
        align-items: flex-start;
        margin-bottom: 40px;
        padding-left: 60px;
    }

    .timeline-item:nth-child(even) {
        flex-direction: column;
    }

    .timeline-date {
        width: 100%;
        text-align: left;
        padding: 0;
        margin-bottom: 15px;
    }

    .timeline-item:nth-child(odd) .timeline-date,
    .timeline-item:nth-child(even) .timeline-date {
        text-align: left;
        padding: 0;
    }

    .timeline-content {
        width: 100%;
        padding: 20px;
    }

    .timeline-content h3 {
        font-size: 18px;
        margin-bottom: 10px;
    }

    .timeline-content p {
        font-size: 14px;
    }

    .timeline-item::before {
        left: 30px;
        transform: none;
    }

    .team-container {
        padding: 0 20px;
    }

    .team-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 30px;
    }

    .avatar-placeholder {
        width: 100px;
        height: 100px;
    }

    .member-name {
        font-size: 18px;
    }

    .member-role {
        font-size: 12px;
    }

    .member-description {
        font-size: 11px;
        max-width: 150px;
    }

    /* 隐藏装饰元素在小屏幕上 */
    .team::after,
    .team-container::before,
    .team-container::after {
        display: none;
    }

    .team-logo {
        flex-direction: column;
        gap: 15px;
    }

    .logo-text {
        margin-left: 0;
    }

    .logo-text::before {
        display: none;
    }

    .team-institution {
        flex-direction: column;
        gap: 15px;
    }

    .institution-text {
        text-align: center;
    }

    .institution-name {
        font-size: 18px;
    }

    .institution-desc {
        font-size: 12px;
    }

    .footer-links {
        flex-direction: column;
        gap: 20px;
    }
}

/* Video placeholder backgrounds */
.video-placeholder-1 {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.video-placeholder-2 {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.video-placeholder-3 {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

.video-placeholder-4 {
    background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
}