/* ============================================
   九紫数智官网 — 响应式 v1.0
   断点: xs<480 / sm 480-767 / md 768-1023 / lg 1024-1279 / xl>=1280
   ============================================ */

/* ---------- ≤ 1023px (Tablet) ---------- */
@media (max-width: 1023px) {
  :root {
    --s12: 72px;
    --s10: 60px;
    --s8: 48px;
  }

  .section__title { font-size: 1.75rem; }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* ---------- ≤ 767px (Mobile) ---------- */
@media (max-width: 767px) {
  :root {
    --s12: 56px;
    --s10: 48px;
    --s8: 40px;
    --s6: 36px;
  }

  .section__title { font-size: 1.5rem; }
  .section__subtitle { font-size: 1rem; }

  /* 导航 — 汉堡菜单 */
  .nav__links {
    position: fixed; top: 64px; left: 0; right: 0;
    flex-direction: column;
    background: rgba(255,255,255,.98);
    backdrop-filter: blur(12px);
    padding: var(--s3);
    gap: var(--s2);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--normal) var(--ease);
    box-shadow: var(--shadow-md);
  }

  .nav__links--open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav__toggle { display: flex; }

  .nav__cta { display: none; }

  /* 页脚 */
  .footer__grid {
    grid-template-columns: 1fr;
    gap: var(--s5);
  }

  .footer__bottom {
    flex-direction: column;
    text-align: center;
  }

  /* 表单 */
  .form-row {
    grid-template-columns: 1fr;
  }

  /* 回到顶部 */
  .back-top {
    bottom: 20px; right: 20px;
    width: 40px; height: 40px;
  }
}

/* ---------- ≤ 480px (Small Mobile) ---------- */
@media (max-width: 479px) {
  .wrap { padding: 0 var(--s2); }
  .btn--lg { padding: 12px 24px; font-size: .95rem; }
}