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

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
}

/* Navigation Bar */
header {
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    color: #333;
    z-index: 1001;
}

/* Mobile menu button */
.menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    cursor: pointer;
    z-index: 1001;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    transition: all 0.3s ease;
}

.nav-links a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    font-size: 1.1rem;
    transition: color 0.3s ease;
    white-space: nowrap;
}

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

/* Dropdown Menu */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #fff;
    min-width: 200px;
    box-shadow: 0 8px 16px rgba(0,0,0,0.1);
    border-radius: 8px;
    z-index: 1;
    padding: 0.5rem 0;
}

.dropdown-content a {
    padding: 0.8rem 1.5rem;
    color: #333;
    text-decoration: none;
    display: block;
    transition: background-color 0.2s ease;
}

.dropdown-content a:hover {
    background-color: #f5f5f5;
}

.dropdown:hover .dropdown-content {
    display: block;
}

/* Hero Section */
.hero {
    min-height: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: white;
    padding: 0rem 2rem;
    /* padding: 2rem 1rem; */
    position: relative;
    overflow: hidden;
}

.hero-content {
    width: 100%;
    max-width: 1200px;
    margin: 2rem auto;
    position: relative;
    z-index: 1;
    padding: 2rem 0;
}

/* .hero-content h1 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: #333;
    line-height: 1.2;
}

.hero-content p {
    font-size: 1.4rem;
    margin-bottom: 2rem;
    color: #555;
} */

.video-container {
    width: 100%;
    max-width: 1200px;
    margin: 2rem 0 0 0;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    height: 0;
    background: #000; /* Black background for letterboxing */
}

#hero-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover; /* Cover the entire container, may crop video */
    background-color: #000; /* Black background for letterboxing */
}

/* Mobile styles */
@media (max-width: 768px) {
    .video-container {
        margin: 1rem auto;
        border-radius: 8px;
    }
}

/* Projects Section */
.projects {
    padding: 0rem 1rem 1rem;
    max-width: 1200px;
    margin: 0.5rem auto 0;
}

.projects h2 {
    text-align: center;
    color: #333;
    margin: 1rem 0 1.5rem;
    font-size: 2rem;
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    margin-top: 1rem;
    width: 100%;
    max-width: 100%;
}

.project-card {
    background: white;
    padding: 1rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    height: 100%;
    border: 1px solid #eee;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}

.project-card h3 {
    margin: 0 0 1rem 0;
    color: #222;
    font-size: 1.2rem;
}

.reason-list {
    list-style: none;
    padding: 0 0 0 2rem;
    margin: 1.2rem 0;
}

.reason-list li {
    position: relative;
    padding-left: 0.5rem;
    margin-bottom: 0.5rem;
    line-height: 1.6;
    color: #333;
    font-size: 0.8rem;
}

.reason-list li:before {
    content: '•';
    position: absolute;
    left: -1.5rem;
    color: #8a2be2;
    font-size: 2em;
    line-height: 0.8;
    vertical-align: middle;
}

.project-btn {
    background: #007bff;
    color: white;
    border: none;
    padding: 0.5rem 1.2rem;
    border-radius: 6px;
    cursor: pointer;
    margin-top: auto;
    transition: all 0.3s ease;
    font-size: 0.9rem;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    align-self: flex-start;
    line-height: 1.2;
}

.project-btn:hover {
    background: #0056b3;
    transform: translateY(-2px);
}

/* 联系部分 */
.contact {
    padding: 6rem 1rem 4rem;
    background-color: #f9f9f9;
}

.contact-container {
    max-width: 1200px;
    margin: 0 auto;
}

.contact-content {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.contact-content h2 {
    text-align: center;
    margin-bottom: 2rem;
    color: #333;
}

.contact-grid {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    align-items: center;
}

.contact-info {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2rem;
    width: 100%;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    min-width: 200px;
}

.contact-item i {
    font-size: 1.5rem;
    color: #007bff;
    width: 2.5rem;
    text-align: center;
}

.contact-item p {
    margin: 0;
    color: #555;
    font-size: 1.1rem;
    white-space: nowrap;
}

.social-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    margin-top: 1rem;
    width: 100%;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    background: #f0f0f0;
    border-radius: 50%;
    color: #555;
    font-size: 1.5rem;
    transition: all 0.3s ease;
    text-decoration: none;
}

.social-link:hover {
    background: #007bff;
    color: white;
    transform: translateY(-3px);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .project-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 992px) {
    .project-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .hero-content h1 {
        font-size: 2.5rem;
    }
}

@media (max-width: 768px) {
    /* Mobile Navigation */
    .menu-btn {
        display: block;
    }
    
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 350px;
        height: 100vh;
        background: white;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        transition: right 0.3s ease;
        box-shadow: -5px 0 15px rgba(0,0,0,0.1);
        padding: 2rem;
        z-index: 1000;
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .dropdown-content {
        position: static;
        box-shadow: none;
        display: none;
        width: 100%;
        padding-left: 1rem;
    }
    
    .dropdown.active .dropdown-content {
        display: block;
    }
    
    /* Hero Section */
    .hero {
        padding-top: 2rem;
        padding-bottom: 1rem;
    }
    
    .hero-content h1 {
        font-size: 2rem;
        margin-bottom: 1rem;
    }
    
    .hero-content p {
        font-size: 1.1rem;
    }
    
    /* Projects */
    .project-grid {
        grid-template-columns: 1fr;
    }
    
    .project-card {
        padding: 1.2rem;
    }
    
    /* Contact Info */
    .contact-info {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 1rem;
    }
    
    .contact-item {
        justify-content: center;
        width: 100%;
    }
}

/* 关于部分 */
.about {
    padding: 1rem;
    background: #f9f9f9;
    max-width: 1200px;
    margin: 0 auto;
}

.about h2 {
    text-align: center;
    margin: 1rem auto;
}

.about-container {
    display: flex;
    gap: 2rem;
    align-items: flex-start;
    margin-bottom: 2rem;
}

.about-text {
    flex: 3;
}

.about-image {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 2rem auto;
    width: 500px;
    height: 375px;
    overflow: hidden;
}

.about-img {
    width: 100%;
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    object-fit: contain;
}

.about p {
    text-align: center;
    line-height: 1.8;
    font-size: 1.1rem;
}

/* 联系部分 */
.contact {
    padding: 5rem 1rem;
    background: white;
}

/* Section Title */
.section-title {
    text-align: center;
    font-size: 2.2rem;
    margin: 3rem auto 2rem;
    max-width: 90%;
    line-height: 1.3;
    color: #333;
}

.section-title br {
    display: block;
    content: "";
    margin: 0.5rem 0;
}

@media (max-width: 768px) {
    .section-title {
        font-size: 1.8rem;
        margin: 2rem auto 1.5rem;
    }
}

/* 研究论文部分 */
.research {
    padding: 1rem 2rem;
    background: #f9f9f9;
    max-width: 1200px;
    margin: 0 auto;
}

.research-container {
    display: flex;
    gap: 1rem;
    align-items: stretch;
    height: 100%;
}

.feature-list {
    flex: 3;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 1.5rem;
    background: #f9f9f9;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.feature-list h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.feature-list ul {
    list-style-position: inside;
    padding-left: 0;
}

.feature-list li {
    margin-bottom: 0.5rem;
    font-size: 1 rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.feature-list li i {
    color: #5808b4;
    font-size: 1rem;
}

.paper-image {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    width: 300px;
    background: #f9f9f9;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.paper-cover {
    width: 100%;
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    object-fit: contain; /* Ensures the entire image is visible */
}

.paper-info {
    flex: 4;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 1.5rem;
    background: #f9f9f9;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.paper-info h3 {
    font-size: 1.3rem;
    margin-bottom: 0.1rem;
}

.paper-info p {
    margin-bottom: 0.1rem;
}

.download-links {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    width: 100%;
}

.download-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    background: #9D00FF;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    text-decoration: none;
    transition: all 0.3s ease;
    font-size: 0.95rem;
    font-weight: 600;
    width: 100%;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.download-btn:hover {
    background: #6E00B3;
}

/* Dataset Examples Section */
.dataset {
    padding: 1rem 1rem;
    color: white;
    text-align: center;
}

.dataset h2 {
    color: white;
    margin-bottom: 0.5rem;
}

.dataset-container {
    display: flex;
    flex-direction: column;
    background: #6a2c70;
    align-items: center;
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    /* padding: 0 1rem; */
    padding: 0rem;
}

.dataset-content p {
    color: white;
    margin-bottom: 2rem;
    font-size: 1.1rem;
    line-height: 1.6;
}

.dataset-image {
    margin: 0 auto;
    display: block;
}

.dataset-img {
    width: 100%;
    max-width: 1200px;
    /* border-radius: 10px; */
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    display: block;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.contact-item i {
    font-size: 1.5rem;
    color: #007bff;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 2rem;
}

.social-links a {
    color: #333;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: #007bff;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero-content h1 {
        font-size: 2rem;
    }
    
    .about-container {
        flex-direction: column;
        align-items: center;
    }
    
    .about-text {
        width: 100%;
        padding: 0 1rem;
        order: 1; /* Ensure text comes first */
    }
    
    .about-image {
        width: 350px;
        height: 262px;
        margin: 2rem 0;
        order: 2; /* Ensure image comes after text */
    }
    
    .research-container {
        flex-direction: column;
        align-items: center;
    }
    
    .paper-image {
        width: 250px;
        margin: 1.5rem 0;
    }
    
    .paper-info {
        text-align: center;
        margin-top: 1.5rem;
    }
    
    .download-links {
        justify-content: center;
    }
}