document.addEventListener('DOMContentLoaded', () => {
    // --- 區塊淡入動畫 ---
    const sections = document.querySelectorAll('section');
    const sectionObserver = new IntersectionObserver(entries => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                entry.target.classList.add('visible');
            }
        });
    }, {
        threshold: 0.05 // *** 降低觸發門檻，修復手機版底部區塊無法顯示問題 ***
    });
    sections.forEach(section => {
        sectionObserver.observe(section);
    });

    // --- 回到頂部按鈕 ---
    const backToTopButton = document.querySelector('.back-to-top');
    window.addEventListener('scroll', () => {
        if (window.pageYOffset > 300) {
            backToTopButton.classList.add('visible');
        } else {
            backToTopButton.classList.remove('visible');
        }
    });

    // --- 導覽列高亮 ---
    const navLinks = document.querySelectorAll('.nav-link');
    const navObserver = new IntersectionObserver(entries => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                const id = entry.target.getAttribute('id');
                navLinks.forEach(link => {
                    link.classList.remove('active');
                    if (link.getAttribute('href') === `#${id}`) {
                        link.classList.add('active');
                    }
                });
            }
        });
    }, {
        rootMargin: '-50% 0px -50% 0px'
    });
    document.querySelectorAll('section[id]').forEach(section => {
        navObserver.observe(section);
    });

    // --- ★★★★★ 修正並簡化後的燈箱功能 ★★★★★ ---
    document.body.addEventListener('click', function(event) {
        // 檢查點擊的是否是帶有 .lightbox-trigger 的 <a> 標籤
        const trigger = event.target.closest('.lightbox-trigger');
        if (trigger) {
            event.preventDefault(); // 阻止連結的默認跳轉行為
            
            const imageUrl = trigger.getAttribute('href');
            
            // 如果頁面上已經有燈箱，就不要再創建
            if (document.querySelector('.lightbox')) {
                return;
            }

            // 創建燈箱元素
            const lightbox = document.createElement('div');
            lightbox.className = 'lightbox';
            lightbox.innerHTML = `<img src="${imageUrl}" alt="放大圖片">`;
            
            // 將燈箱加入到 body
            document.body.appendChild(lightbox);

            // 監聽點擊燈箱本身以關閉
            lightbox.addEventListener('click', () => {
                lightbox.classList.add('closing');
                setTimeout(() => {
                    if (document.body.contains(lightbox)) {
                        document.body.removeChild(lightbox);
                    }
                }, 300); // 等待淡出動畫結束
            });
        }
    });
});