document.addEventListener('DOMContentLoaded', () => {
    // Theme toggle
    const themeToggle = document.getElementById('theme-toggle');
    const htmlElement = document.documentElement;

    // Set initial theme based on saved preference or system setting
    if (localStorage.getItem('theme') === 'dark' || (!('theme' in localStorage) && window.matchMedia('(prefers-color-scheme: dark)').matches)) {
        htmlElement.classList.add('dark');
    } else {
        htmlElement.classList.remove('dark');
    }

    themeToggle.addEventListener('click', () => {
        if (htmlElement.classList.contains('dark')) {
            htmlElement.classList.remove('dark');
            localStorage.setItem('theme', 'light');
        } else {
            htmlElement.classList.add('dark');
            localStorage.setItem('theme', 'dark');
        }
    });

    // Scroll animations
    const observer = new IntersectionObserver((entries) => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                entry.target.classList.add('fade-in-up-visible');
            }
        });
    }, {
        threshold: 0.1
    });

    document.querySelectorAll('.fade-in-up').forEach(el => {
        observer.observe(el);
    });
});