(() => {
  'use strict';

  const body = document.body;
  const root = document.documentElement;
  if (!body || root.dataset.v710Runtime === 'ready') return;
  root.dataset.v710Runtime = 'ready';

  // V7.0.16 is the approved homepage interaction baseline.
  if (body.dataset.v710Family === 'home') return;

  const reduceMotion = window.matchMedia?.('(prefers-reduced-motion: reduce)').matches;
  if (reduceMotion) body.classList.add('v710-reduce-motion');

  // Preserve a clear language boundary: pages without an approved English body
  // continue to the English homepage instead of presenting partial translation.
  const fallbackLanguage = document.querySelector('[data-language-home-fallback]');
  if (fallbackLanguage) {
    fallbackLanguage.setAttribute('aria-label', 'Open the English homepage');
    fallbackLanguage.setAttribute('title', '进入英文首页（当前页面正文为中文）');
  }

  // Mark the current local route consistently in contextual and footer navigation.
  const current = decodeURIComponent(location.pathname.split('/').pop() || 'index.html');
  document.querySelectorAll('main nav a[href], footer a[href]').forEach((link) => {
    const raw = link.getAttribute('href') || '';
    if (!raw || /^(?:https?:|mailto:|tel:|#)/i.test(raw)) return;
    const file = decodeURIComponent(raw.split('#')[0].split('?')[0].replace(/^\.\//, '')) || current;
    if (file === current && !link.closest('[data-v710-ignore-current]')) {
      link.dataset.v710CurrentRoute = 'true';
    }
  });

  // Ensure external links opened in a new tab retain the expected security relation.
  document.querySelectorAll('a[target="_blank"]').forEach((link) => {
    const rel = new Set((link.getAttribute('rel') || '').split(/\s+/).filter(Boolean));
    rel.add('noopener');
    link.setAttribute('rel', [...rel].join(' '));
  });

  // Lazy images below the first content screen should not compete with the hero.
  document.querySelectorAll('main img').forEach((image, index) => {
    if (index > 1 && !image.hasAttribute('loading')) image.loading = 'lazy';
    if (!image.hasAttribute('decoding')) image.decoding = 'async';
  });
})();