:root {
    --primary-color: #1a237e;
    --secondary-color: #0d47a1;
    --accent-color: #2196f3;
    --text-color: #333333;
    --light-gray: #f5f5f5;
    --dark-gray: #666666;
    --white: #ffffff;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--light-gray);
}

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

/* Header Styles */
.main-header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

.main-header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
}

.main-nav {
    padding: 1rem 0;
}

.main-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo a {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: 700;
    transition: var(--transition);
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--accent-color);
}

/* Hero Section */
.hero-section {
    background: linear-gradient(rgba(26,35,126,0.9), rgba(26,35,126,0.9)), url('images/hero-bg.jpg');
    background-size: cover;
    background-position: center;
    color: var(--white);
    text-align: center;
    padding: 10rem 0 6rem;
    margin-bottom: 4rem;
}

.hero-section h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    font-family: 'Playfair Display', serif;
    line-height: 1.2;
}

.hero-section p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.9;
}

/* Research Section */
.research-highlights {
    padding: 4rem 0;
}

.research-highlights h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--primary-color);
    font-family: 'Playfair Display', serif;
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.research-card {
    background: var(--white);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.research-card img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.research-card:hover img {
    transform: scale(1.05);
}

/* Publications Section */
.publications {
    padding: 4rem 0;
    background: var(--white);
}

.publications h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--primary-color);
    font-family: 'Playfair Display', serif;
}

.publication-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--light-gray);
    border-radius: 10px;
    transition: var(--transition);
}

.publication-item:hover {
    transform: translateX(10px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.pub-date {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-color);
    min-width: 80px;
}

/* Team Section */
.team {
    padding: 4rem 0;
}

.team h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--primary-color);
    font-family: 'Playfair Display', serif;
}

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

.team-member {
    text-align: center;
}

.team-member img {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    margin-bottom: 1rem;
    object-fit: cover;
}

.team-member h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

/* Subscribe Section */
.subscribe-section {
    background: var(--white);
    padding: 5rem 0;
    margin-top: 4rem;
    border-radius: 20px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.subscribe-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.subscribe-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
    font-family: 'Playfair Display', serif;
}

.subscribe-form {
    margin-top: 2rem;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 1rem;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus {
    border-color: var(--accent-color);
    outline: none;
    box-shadow: 0 0 0 2px rgba(33,150,243,0.1);
}

.subscribe-submit {
    background: var(--accent-color);
    color: var(--white);
    border: none;
    padding: 1rem 2rem;
    border-radius: 25px;
    cursor: pointer;
    font-weight: 500;
    width: 100%;
    transition: var(--transition);
}

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

/* Footer */
.main-footer {
    background: var(--primary-color);
    color: var(--white);
    padding: 4rem 0 1rem;
    margin-top: 4rem;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-info h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.footer-contact h4 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
}

.footer-contact p {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.footer-social {
    display: flex;
    gap: 1rem;
}

.footer-social a {
    color: var(--white);
    font-size: 1.4rem;
    transition: var(--transition);
}

.footer-social a:hover {
    color: var(--accent-color);
    transform: translateY(-3px);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .container {
        padding: 0 30px;
    }
}

@media (max-width: 768px) {
    .hero-section h1 {
        font-size: 2.5rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-contact p {
        justify-content: center;
    }
    
    .footer-social {
        justify-content: center;
    }
    
    .nav-links {
        display: none;
    }
}

@media (max-width: 480px) {
    .hero-section h1 {
        font-size: 2rem;
    }
    
    .research-grid,
    .team-grid {
        grid-template-columns: 1fr;
    }
    
    .publication-item {
        flex-direction: column;
        gap: 1rem;
    }
}