astro_avtourist/frontend/src/components/blog/ArticleTableOfContents.astro

---
interface TOCItem {
  id: string;
  text: string;
  level: number;
}
interface Props {
  items: TOCItem[];
}
const { items } = Astro.props;
---

{items.length > 0 && (
<aside class="toc-container" id="toc-sidebar">
  <nav class="toc-nav">
    <h3 class="toc-title">Оглавление</h3>
    <ul class="toc-list">
      {items.map((item) => (
          <li class={`toc-item level-${item.level}`} data-toc-target={item.id}>
            <a href={`#${item.id}`} class="toc-link">
              <span class="toc-text">{item.text}</span>
            </a>
          </li>
      ))}
    </ul>
  </nav>
</aside>
    )}

<style is:global>
  .toc-container { 
    width: 100%; 
    margin-top: 1.5rem;
    transition: margin-top 0.3s ease;
  }
  .toc-container.no-top-margin {
    margin-top: 0 !important;
  }
  .toc-nav {
    background: #ffffff;
    border-radius: 1.25rem;
    padding: 1.5rem;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
  }
  .toc-title {
    color: #1e3050;
    font-size: 1.1rem;
    font-weight: 800;
    margin: 0 0 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid #eac26e;
    text-align: center;
  }

  .toc-list {
    list-style: none;
    padding: 0;
    margin: 0;
    counter-reset: toc-h2;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
  }

  /* Номера только для H2 (level-1/2), H3 без номеров */
  .toc-item.level-1, .toc-item.level-2 { counter-reset: toc-h3; counter-increment: toc-h2; }
  .toc-item.level-3 { padding-left: 1.25rem; counter-increment: toc-h3; }
  .toc-item.level-3 .toc-link::before { content: none; }

  /* h2 = level 1 в HTML */
  .toc-item.level-1, .toc-item.level-2 {
    font-weight: 600;
  }
  .toc-item.level-1 .toc-link, .toc-item.level-2 .toc-link {
    font-size: 0.95rem;
    padding: 0.6rem 0.75rem;
  }

  .toc-link {
    display: flex;
    padding: 0.5rem 0.75rem;
    color: #64748b;
    text-decoration: none;
    font-size: 0.9rem;
    line-height: 1.4;
    border-radius: 0.5rem;
    transition: all 0.2s ease;
  }

  .toc-link::before {
    content: "";
    display: inline-block;
    width: 1.5rem;
    color: #1e3050;
    font-weight: 700;
    margin-right: 0.6rem;
    flex-shrink: 0;
    text-align: center;
  }
  .toc-item.level-1 .toc-link::before, .toc-item.level-2 .toc-link::before { content: counter(toc-h2) "."; }
  /* H3 без номеров */

  .toc-link:hover { color: #1e3050; background: #f1f5f9; }

  .toc-item.active .toc-link {
    color: #eac26e;
    font-weight: 700;
    background: rgba(234, 194, 110, 0.1);
  }
  .toc-item.active .toc-link::before { color: #eac26e; }
</style>

<script>
  function setupTOC() {
    const toc = document.getElementById('toc-sidebar');
    if (!toc) return;

    let lastScrollY = window.scrollY;
    let ticking = false;

    const updateMargin = () => {
      const currentScrollY = window.scrollY;
      // При скролле ВНИЗ - убрать отступ
      if (currentScrollY > lastScrollY) {
        toc.classList.add('no-top-margin');
      } else {
        // При скролле ВВЕРХ или начальная позиция - вернуть отступ
        toc.classList.remove('no-top-margin');
      }
      lastScrollY = currentScrollY;
      ticking = false;
    };

    window.addEventListener('scroll', () => {
      if (!ticking) {
        requestAnimationFrame(() => updateMargin());
        ticking = true;
      }
    });

    const items = toc.querySelectorAll('.toc-item');
    const links = toc.querySelectorAll<HTMLAnchorElement>('.toc-link');
    const HEADER_OFFSET = 120; // Высота хедера + запас

    // --- 1. ПЛАВНЫЙ СКРОЛЛ ПРИ КЛИКЕ ---
    links.forEach(link => {
      link.addEventListener('click', (e) => {
        e.preventDefault();
        const id = link.getAttribute('href')?.substring(1);
        const target = document.getElementById(id || '');

        if (target) {
          const elementPosition = target.getBoundingClientRect().top;
          const offsetPosition = elementPosition + window.pageYOffset - HEADER_OFFSET;

          window.scrollTo({
            top: offsetPosition,
            behavior: "smooth"
          });

          // Обновляем URL
          history.pushState(null, '', `#${id}`);
        }
      });
    });

    // --- 2. ПОДСВЕТКА ПРИ СКРОЛЛЕ (SCROLL SPY) ---
    const headingElements = Array.from(items)
        .map(item => {
          const id = item.getAttribute('data-toc-target');
          return id ? document.getElementById(id) : null;
        })
        .filter((el): el is HTMLElement => el !== null);

    const observerOptions = {
      root: null,
      rootMargin: '-120px 0px -70% 0px', // Зона срабатывания: верхняя часть экрана
      threshold: 0
    };

    const observer = new IntersectionObserver((entries) => {
      entries.forEach(entry => {
        if (entry.isIntersecting) {
          const activeId = entry.target.id;

          items.forEach(item => {
            if (item.getAttribute('data-toc-target') === activeId) {
              item.classList.add('active');
            } else {
              item.classList.remove('active');
            }
          });
        }
      });
    }, observerOptions);

    headingElements.forEach(heading => observer.observe(heading));
  }

  // Запуск для обычной загрузки и для Astro ViewTransitions
  document.addEventListener('DOMContentLoaded', setupTOC);
  document.addEventListener('astro:page-load', setupTOC);
</script>