script.js

// Smooth scrolling for navigation links
document.querySelectorAll('a[href^="#"]').forEach(anchor => {
    anchor.addEventListener('click', function (e) {
        e.preventDefault();
        const target = document.querySelector(this.getAttribute('href'));
        if (target) {
            target.scrollIntoView({
                behavior: 'smooth',
                block: 'start'
            });
        }
    });
});

// Add active class to navigation items on scroll
window.addEventListener('scroll', () => {
    let current = '';
    const sections = document.querySelectorAll('section');
    const navLinks = document.querySelectorAll('.nav-links a');

    sections.forEach(section => {
        const sectionTop = section.offsetTop;
        const sectionHeight = section.clientHeight;
        if (pageYOffset >= sectionTop - 200) {
            current = section.getAttribute('id');
        }
    });

    navLinks.forEach(link => {
        link.classList.remove('active');
        if (link.getAttribute('href').slice(1) === current) {
            link.classList.add('active');
        }
    });
});

// Add fade-in animation on scroll
const observerOptions = {
    threshold: 0.1,
    rootMargin: '0px 0px -50px 0px'
};

const observer = new IntersectionObserver((entries) => {
    entries.forEach(entry => {
        if (entry.isIntersecting) {
            entry.target.style.opacity = '1';
            entry.target.style.transform = 'translateY(0)';
        }
    });
}, observerOptions);

// Observe elements for fade-in animation
document.addEventListener('DOMContentLoaded', () => {
    const animateElements = document.querySelectorAll('.research-card, .publication-item, .project-card, .cv-section, .contact-item');
    
    animateElements.forEach(el => {
        el.style.opacity = '0';
        el.style.transform = 'translateY(20px)';
        el.style.transition = 'opacity 0.6s ease, transform 0.6s ease';
        observer.observe(el);
    });
});