:root {
    --primary-color: #0056b3;
    --secondary-color: #00a8cc;
    --accent-color: #e6f2ff;
    --text-dark: #333333;
    --text-light: #666666;
    --white: #ffffff;
    --bg-light: #f8f9fa;
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    color: var(--text-dark);
    line-height: 1.6;
    padding-top: 80px; /* Offset for fixed header */
}

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

/* Typography */
h1, h2, h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

p {
    color: var(--text-light);
    margin-bottom: 15px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
}

.btn-primary:hover {
    background-color: #004494;
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: var(--white);
}

.btn-light {
    background-color: var(--white);
    color: var(--primary-color);
}

.btn-light:hover {
    background-color: var(--bg-light);
}

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

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

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

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

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

.mobile-menu-btn {
    display: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    padding: 120px 0 100px;
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--white) 100%);
    text-align: center;
}

.hero-content h1 {
    font-size: 48px;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.hero-content p {
    font-size: 20px;
    max-width: 800px;
    margin: 0 auto 40px;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
}

/* Stats Section */
.stats {
    background-color: var(--primary-color);
    padding: 60px 0;
    color: var(--white);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
    text-align: center;
}

.stat-item h3 {
    color: var(--white);
    font-size: 48px;
    margin-bottom: 10px;
}

.stat-item p {
    color: var(--accent-color);
    font-size: 18px;
    margin: 0;
}

/* Research Areas */
.research-areas {
    padding: 100px 0;
    background-color: var(--bg-light);
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 36px;
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    text-align: center;
    transition: var(--transition);
    border-bottom: 4px solid transparent;
}

.card:hover {
    transform: translateY(-10px);
    border-bottom-color: var(--secondary-color);
    box-shadow: 0 15px 30px rgba(0,0,0,0.1);
}

.card i {
    font-size: 48px;
    color: var(--secondary-color);
    margin-bottom: 20px;
}

.card h3 {
    font-size: 22px;
    margin-bottom: 15px;
}

/* CTA Section */
.cta-section {
    padding: 100px 0;
    background: linear-gradient(rgba(0, 86, 179, 0.85), rgba(0, 86, 179, 0.85)), url('https://images.unsplash.com/photo-1579154204601-01588f351e67?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80') center/cover;
    color: var(--white);
    text-align: center;
}

.cta-content h2 {
    color: var(--white);
    font-size: 36px;
}

.cta-content p {
    color: var(--accent-color);
    font-size: 18px;
    max-width: 700px;
    margin: 0 auto 30px;
}

/* Footer */
footer {
    background-color: #1a1a1a;
    color: var(--white);
    padding: 80px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 60px;
}

.footer-about .logo {
    color: var(--white);
    margin-bottom: 20px;
}

.footer-about p, .footer-contact p {
    color: #999;
}

.footer-links h4, .footer-contact h4 {
    color: var(--white);
    margin-bottom: 20px;
    font-size: 18px;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: #999;
    text-decoration: none;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--secondary-color);
}

.footer-contact i {
    color: var(--secondary-color);
    width: 20px;
    margin-right: 10px;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #333;
    color: #666;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links, .header-btn {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }

    .hero-content h1 {
        font-size: 36px;
    }

    .hero-buttons {
        flex-direction: column;
    }
    
    .nav-active {
        display: flex !important;
        flex-direction: column;
        position: absolute;
        top: 80px;
        left: 0;
        width: 100%;
        background: var(--white);
        padding: 20px;
        box-shadow: 0 10px 10px rgba(0,0,0,0.1);
        text-align: center;
    }
}