/* ============================================================
   响应式适配
   ============================================================ */

/* ---------- ≤1440px：收窄侧栏 ---------- */
@media (max-width: 1440px) {
  :root { --rail-w: 178px; }
  .shell { gap: var(--sp-4); }
  .hero__main { min-height: 420px; }
}

/* ---------- ≤1200px：隐藏右侧栏，保留左侧栏 ---------- */
@media (max-width: 1200px) {
  .shell { grid-template-columns: 172px minmax(0, 1fr); }
  .rail--right { display: none; }
  .nav__link { padding: 0 11px; font-size: var(--fs-sm); }
  .dropdown--wide { min-width: 460px; }
  .topbar__slogan { gap: 14px; }
  .topbar__slogan-col li { font-size: 11px; }
}

/* ---------- ≤1024px：单列，侧栏移到底部 ---------- */
@media (max-width: 1024px) {
  .shell { grid-template-columns: minmax(0, 1fr); }
  .rail { position: static; padding: 0 0 var(--sp-5); }
  .rail--left { order: 3; }
  .rail--right { display: block; order: 4; }
  .main { order: 1; }
  .rail__blocks {
    display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-4);
  }
  .hero__grid { grid-template-columns: 1fr; }
  .hero__main { grid-row: auto; min-height: 380px; }
  .hero__side { min-height: 190px; }
  .about { grid-template-columns: 1fr; padding: var(--sp-6) var(--sp-5); }
  .footer__top { grid-template-columns: 1fr 1fr; gap: var(--sp-5); }
  .footer__slogan { flex-wrap: wrap; gap: var(--sp-5); }
  .act-grid { grid-template-columns: 1fr; }
}

/* ---------- ≤900px：移动导航 ---------- */
@media (max-width: 900px) {
  :root { --nav-h: 64px; --topbar-h: 48px; }

  .nav__inner { grid-template-columns: 1fr auto; }
  .nav__burger { display: block; }
  .nav__burger.is-open span:nth-child(1),
  .nav__burger.is-open span:nth-child(2),
  .nav__burger.is-open span:nth-child(3) { transform: none; opacity: 1; }
  .nav__burger.is-open { background: var(--blue-50); }

  .nav__menu {
    position: absolute; top: 100%; right: 8px; left: auto;
    width: auto; height: auto;
    min-width: 140px; max-width: calc(100vw - 16px);
    background: var(--white);
    display: flex; flex-direction: column; align-items: stretch; justify-content: flex-start;
    gap: 0; padding: 0;
    border: 1px solid var(--border); border-radius: var(--r-lg);
    box-shadow: 0 16px 40px rgba(15,30,60,.18);
    transform: translateY(-8px); opacity: 0; visibility: hidden;
    transition: transform .25s ease, opacity .25s ease, visibility .25s ease;
    z-index: 55;
  }
  .nav__menu.is-open { transform: translateY(0); opacity: 1; visibility: visible; }
  .nav__item { height: auto; flex-direction: column; align-items: stretch; }
  .nav__link {
    min-height: 0; padding: 8px 12px; justify-content: flex-start;
    border-bottom: none; border-radius: 0; font-size: var(--fs-sm);
    color: var(--ink-700); transition: background .16s, color .16s;
  }
  .nav__menu .nav__link:first-child { border-top-left-radius: var(--r-lg); border-top-right-radius: var(--r-lg); }
  .nav__menu .nav__link:last-child { border-bottom-left-radius: var(--r-lg); border-bottom-right-radius: var(--r-lg); }
  .nav__menu .nav__link:hover { background: var(--blue-50); color: var(--blue-700); }
  .nav__menu .nav__link.is-active { background: var(--blue-500); color: var(--white); font-weight: 600; }
  .nav__link::after { display: none; }
  .nav__item.is-expanded .nav__caret { transform: rotate(180deg); }

  .dropdown {
    position: static; transform: none; opacity: 1; visibility: visible;
    box-shadow: none; border: none; border-radius: 0;
    min-width: 0; padding: 0; max-height: 0; overflow: hidden;
    background: var(--blue-25);
    transition: max-height .3s ease, padding .3s ease;
  }
  .nav__item.is-expanded .dropdown { max-height: 720px; padding: var(--sp-3) 0; }
  .nav__item:hover .dropdown { transform: none; }
  .dropdown { display: none; }
  .nav__caret { display: none; }
  .dropdown--wide { min-width: 0; }
  .dropdown__grid { grid-template-columns: 1fr; gap: 0; }
  .dropdown a { padding: 10px 16px; font-size: var(--fs-sm); line-height: 1.45; }

  /* 顶栏：移动端显示 Slogan 于页面最上方（中英上下堆叠） */
  .topbar { height: auto; }
  .topbar__inner {
    flex-direction: column; height: auto; align-items: stretch;
    gap: var(--sp-3); padding: var(--sp-3) var(--sp-3);
  }
  .topbar__slogan {
    display: flex; flex-direction: column; align-items: center;
    gap: 10px; font-size: var(--fs-xs);
  }
  .topbar__slogan-col { align-items: flex-start; text-align: left; width: 100%; max-width: 520px; }
  .topbar__slogan-col li { justify-content: flex-start; }
  .topbar__tools { width: 100%; justify-content: flex-start; gap: 6px; }
  .tool { height: auto; padding: 6px 8px; min-width: 44px; min-height: 48px; justify-content: center; flex-direction: column; gap: 2px; font-size: 10px; line-height: 1.15; }
  .tool svg { width: 18px; height: 18px; }
  .tool span.txt { display: block; text-align: center; }
  .tool--emergency br { display: none; }
  .tool--emergency .tool__tel { display: none; }
  .fs-group { padding: 0 6px; }
  .fs-btn { padding: 4px 7px; }
  .lang { margin-left: 0; }
  .lang__menu {
    position: absolute; top: 100%; right: 0; left: auto;
    width: auto; transform: none;
    min-width: 130px; white-space: nowrap;
    border: 1px solid var(--border); border-radius: var(--r-lg);
    box-shadow: 0 16px 40px rgba(15,30,60,.18); padding: 0;
  }
  .lang:hover .lang__menu, .lang:focus-within .lang__menu, .lang.is-open .lang__menu { transform: none; }
  .lang__menu a { display: block; padding: 8px 12px; border-radius: 0; }
  .lang__menu a:first-child { border-top-left-radius: var(--r-lg); border-top-right-radius: var(--r-lg); }
  .lang__menu a:last-child { border-bottom-left-radius: var(--r-lg); border-bottom-right-radius: var(--r-lg); }

  /* 内容 */
  .shell { padding: 0 var(--sp-4); }
  .section { padding: var(--sp-6) 0; }
  .section__title { font-size: var(--fs-xl); }
  .hero__main { min-height: 420px; }
  .ai-search__box { flex-direction: column; padding: var(--sp-3); border-radius: var(--r-lg); align-items: stretch; }
  .ai-search__box input { padding: 10px 12px; border: 1px solid var(--border); border-radius: var(--r-md); }
  .ai-search__submit { justify-content: center; border-radius: var(--r-md); }
  .act-block { grid-template-columns: 1fr; }
  .act-block__media { min-height: 150px; order: -1; }
  .footer__top { grid-template-columns: 1fr; }
  .footer__slogan { flex-direction: column; text-align: center; gap: var(--sp-4); padding: var(--sp-5) 0; }
  .footer__slogan-logo .logo__img { height: 56px; }
  .footer__slogan-col { min-width: unset; max-width: none; }
  .footer__bottom { flex-direction: column; align-items: flex-start; gap: var(--sp-3); }
  .to-top { right: 16px; bottom: 16px; width: 42px; height: 42px; }
}

/* ---------- ≤600px ---------- */
@media (max-width: 600px) {
  :root { --nav-h: 58px; }
  .rail__blocks { grid-template-columns: 1fr; }
  .hero__main { min-height: 360px; }
  .section__title { font-size: var(--fs-lg); }
  .logo__img { height: 40px; }
  .topbar__slogan { font-size: 10px; gap: 7px; }
  .topbar__slogan-col li { font-size: 10px; }
  .footer__slogan-col span { white-space: normal; font-size: var(--fs-xs); }
  .footer__slogan-col b { font-size: var(--fs-sm); }
}

/* ---------- 打印 ---------- */
@media print {
  .topbar, .nav, .to-top, .rail, .ad-slot, .partner-card--ad { display: none !important; }
  .shell { grid-template-columns: 1fr; }
  body { background: #FFF; }
  .section { padding: 16px 0; break-inside: avoid; }
}