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

:root {
    --primary-color: #000000;
    --secondary-color: #333333;
    --accent-color: #555555;
    --text-color: #333333;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --shadow: 0 2px 4px rgba(0,0,0,0.1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

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

/* Navigation */
.navbar {
    background: var(--white);
    box-shadow: var(--shadow);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
}

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

.nav-menu a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    background: var(--light-bg);
    padding: 120px 0 60px;
    margin-top: 70px;
}

.hero-content {
    text-align: center;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    color: var(--primary-color);
}

.hero-subtitle {
    margin-top: 0.5rem;
    font-size: 1.1rem;
    color: var(--text-color);
}

/* Sections */
.section {
    padding: 60px 0;
}

.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 3rem;
    color: var(--primary-color);
}

/* Research Section */
.research {
    background: var(--white);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.research-card {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 8px;
    text-align: center;
    transition: transform 0.3s;
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.research-icon i {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.research-card h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.research-card p {
    color: var(--text-color);
}

/* Publications Section */
.publications-preview {
    background: var(--light-bg);
}

.publications-list {
    max-width: 900px;
    margin: 0 auto;
}

.publication-item {
    background: var(--white);
    padding: 2rem;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--primary-color);
    border-radius: 0 8px 8px 0;
}

.publication-title {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.publication-authors {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.publication-authors strong {
    color: var(--primary-color);
    font-weight: 600;
}

.publication-journal {
    font-style: italic;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.publication-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s;
}

.publication-link:hover {
    color: var(--secondary-color);
}

.publication-link i {
    margin-left: 5px;
    transition: transform 0.3s;
}

.publication-link:hover i {
    transform: translateX(3px);
}

/* Publications Page Specific */
.publications-section {
    padding: 80px 0;
}

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

.year-header {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.year-header h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-right: 1rem;
}

.year-header .line {
    flex: 1;
    height: 2px;
    background: #e0e0e0;
}

.publications-section .publication-item h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.authors {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.authors strong {
    color: var(--primary-color);
    font-weight: 600;
}

.journal {
    font-style: italic;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

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

.pub-links a {
    color: var(--primary-color);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border: 1px solid var(--primary-color);
    border-radius: 4px;
    transition: all 0.3s;
    font-size: 0.9rem;
}

.pub-links a:hover {
    background: var(--primary-color);
    color: var(--white);
}

/* Team Section */
.team-preview {
    background: var(--white);
}

.team-description {
    text-align: center;
    color: var(--text-color);
    margin-bottom: 2rem;
}

.team-section {
    padding: 80px 0;
}

.team-section h3 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 3rem;
    color: var(--primary-color);
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.team-card {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
    text-align: center;
}

.team-card.placeholder {
    opacity: 0.6;
    border: 2px dashed #ddd;
}

.avatar-placeholder {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: #e5e7eb;
    margin: 0 auto 1.5rem;
}

.team-card h4 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.team-card p {
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.team-card .muted {
    color: #999;
    font-size: 0.9rem;
}

/* Contact Section */
.contact {
    background: var(--light-bg);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
    max-width: 800px;
    margin: 0 auto;
}

.contact-item {
    text-align: center;
}

.contact-icon i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.contact-item h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.contact-item p {
    color: var(--text-color);
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* Buttons */
.cta-container {
    text-align: center;
    margin-top: 2rem;
}

.btn-primary {
    display: inline-block;
    padding: 0.75rem 2rem;
    background: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 4px;
    transition: all 0.3s;
    font-weight: 500;
}

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* Footer */
.footer {
    background: var(--primary-color);
    color: var(--white);
    text-align: center;
    padding: 2rem 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0,0,0,0.05);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }
    
    .nav-toggle {
        display: flex;
    }

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

    .nav-toggle.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .publication-item {
        padding: 1.5rem;
    }
    
    .pub-links {
        flex-direction: column;
    }
    
    .pub-links a {
        text-align: center;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }
}