/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

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

/* Navigation */
.navbar {
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: #333;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    color: #666;
    text-decoration: none;
    font-weight: 400;
    transition: color 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: #333;
    font-weight: 500;
}

/* Main content */
.main-content {
    padding: 2rem 0;
    min-height: calc(100vh - 120px);
}

/* Hero section */
.hero-section {
    margin-bottom: 3rem;
}

.hero-content {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 2rem;
    align-items: center;
}

.profile-image {
    display: flex;
    justify-content: center;
}

.profile-img {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid #f0f0f0;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #333;
}

.hero-subtitle {
    font-size: 1.3rem;
    color: #666;
    margin-bottom: 0.3rem;
}

.hero-institution {
    font-size: 1.1rem;
    color: #888;
    margin-bottom: 1rem;
}

.contact-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.contact-link {
    color: #0066cc;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.contact-link:hover {
    color: #004499;
}

/* Sections */
.about-section,
.news-section {
    margin-bottom: 3rem;
}

.about-section h2,
.news-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #333;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 0.5rem;
}

.about-section h3 {
    font-size: 1.3rem;
    font-weight: 500;
    margin: 1.5rem 0 1rem 0;
    color: #333;
}

.about-section p {
    margin-bottom: 1rem;
    color: #555;
    font-size: 1rem;
}

.research-interests {
    list-style: none;
    padding-left: 0;
}

.research-interests li {
    padding: 0.5rem 0;
    color: #555;
    position: relative;
    padding-left: 1.5rem;
}

.research-interests li::before {
    content: "•";
    color: #0066cc;
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* News section */
.news-item {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    padding: 0.5rem 0;
}

.news-date {
    font-weight: 500;
    color: #666;
    min-width: 100px;
}

.news-text {
    color: #555;
}

/* Footer */
.footer {
    background-color: #f8f9fa;
    padding: 2rem 0;
    margin-top: 3rem;
    border-top: 1px solid #e9ecef;
}

.footer p {
    text-align: center;
    color: #666;
    font-size: 0.9rem;
}

/* Research page specific styles */
.research-intro {
    margin-bottom: 3rem;
}

.research-intro h1 {
    font-size: 2.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #333;
}

.research-intro p {
    font-size: 1.1rem;
    color: #555;
    line-height: 1.7;
}

.publications-section {
    margin-bottom: 3rem;
}

.publications-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: #333;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 0.5rem;
}

.year-group {
    margin-bottom: 2rem;
}

.year-header {
    font-size: 1.4rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 1rem;
    padding-left: 1rem;
    border-left: 4px solid #0066cc;
}

.publication {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background-color: #fafafa;
    border-radius: 8px;
    border-left: 3px solid #e0e0e0;
    transition: all 0.3s ease;
}

.publication:hover {
    background-color: #f5f5f5;
    border-left-color: #0066cc;
}

.pub-title {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: #333;
}

.pub-authors {
    font-size: 0.95rem;
    color: #666;
    margin-bottom: 0.3rem;
}

.pub-venue {
    font-size: 0.9rem;
    color: #888;
    margin-bottom: 0.8rem;
}

.pub-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.pub-link {
    color: #0066cc;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.3rem 0.8rem;
    border: 1px solid #0066cc;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.pub-link:hover {
    background-color: #0066cc;
    color: white;
}

.research-interests-section {
    margin-bottom: 3rem;
}

.research-interests-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: #333;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 0.5rem;
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.interest-item {
    padding: 1.5rem;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e9ecef;
}

.interest-item h4 {
    font-size: 1.2rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.8rem;
}

.interest-item p {
    color: #555;
    line-height: 1.6;
}

.collaboration-section {
    margin-bottom: 3rem;
}

.collaboration-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #333;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 0.5rem;
}

.collaboration-section p {
    color: #555;
    margin-bottom: 1rem;
    line-height: 1.7;
}

.collaboration-details {
    margin-top: 2rem;
}

.collaboration-details h3 {
    font-size: 1.3rem;
    font-weight: 500;
    color: #333;
    margin: 1.5rem 0 0.8rem 0;
}

.collaboration-details p {
    color: #555;
    margin-bottom: 1rem;
}

/* CV page specific styles */
.cv-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #f0f0f0;
}

.cv-header h1 {
    font-size: 2.2rem;
    font-weight: 600;
    color: #333;
}

.download-btn {
    background-color: #0066cc;
    color: white;
    padding: 0.8rem 1.5rem;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.download-btn:hover {
    background-color: #004499;
}

.cv-section {
    margin-bottom: 3rem;
}

.cv-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: #333;
    border-bottom: 2px solid #f0f0f0;
    padding-bottom: 0.5rem;
}

.cv-item {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background-color: #fafafa;
    border-radius: 8px;
    border-left: 4px solid #e0e0e0;
}

.cv-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.8rem;
}

.cv-item-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: #333;
    margin: 0;
}

.cv-date {
    font-weight: 500;
    color: #666;
    font-size: 0.95rem;
}

.cv-item-details {
    color: #555;
}

.cv-item-details p {
    margin-bottom: 0.5rem;
}

.cv-item-details ul {
    margin-left: 1.5rem;
    margin-top: 0.5rem;
}

.cv-item-details li {
    margin-bottom: 0.3rem;
}

.publication-list {
    margin-bottom: 1rem;
}

.pub-item {
    margin-bottom: 1rem;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: 6px;
    border-left: 3px solid #e0e0e0;
}

.pub-title {
    font-weight: 600;
    color: #333;
    margin-bottom: 0.3rem;
}

.pub-authors {
    font-size: 0.95rem;
    color: #666;
    margin-bottom: 0.2rem;
}

.pub-venue {
    font-size: 0.9rem;
    color: #888;
    font-style: italic;
}

.pub-note {
    font-size: 0.9rem;
    color: #666;
    font-style: italic;
}

.service-item {
    margin-bottom: 1.5rem;
}

.service-item h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
}

.service-item ul {
    margin-left: 1.5rem;
}

.service-item li {
    margin-bottom: 0.3rem;
    color: #555;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.skill-category {
    padding: 1.5rem;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e9ecef;
}

.skill-category h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.8rem;
}

.skill-category p {
    color: #555;
    line-height: 1.6;
}

/* Responsive design */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: 1rem 20px;
    }
    
    .nav-menu {
        margin-top: 1rem;
        gap: 1rem;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 1rem;
    }
    
    .profile-img {
        width: 150px;
        height: 150px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .contact-links {
        justify-content: center;
    }
    
    .news-item {
        flex-direction: column;
        gap: 0.3rem;
    }
    
    .news-date {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero-title {
        font-size: 1.8rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .contact-links {
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
    }
    
    /* CV page responsive */
    .cv-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .cv-item-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .cv-date {
        align-self: flex-end;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
}