/* ========== RESPONSIVE ========== */
@media (max-width: 1024px) {
  .about-grid,
  .iedu-wrap {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .about-stats {
    max-width: 400px;
  }

  .iedu-visual {
    height: 360px;
  }

  .adv-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .adv-item {
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }

  .adv-item:nth-child(2) {
    border-right: none;
  }

  .eight-adv-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .case-card:first-child {
    grid-row: auto;
  }

  .case-card:first-child .case-body {
    display: block;
  }

  .case-overlay-text {
    display: none !important;
  }

  .case-card:first-child .case-visual {
    height: 180px;
    min-height: auto;
  }

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

@media (max-width: 768px) {
  :root {
    --nav-height: 60px;
  }

  .nav-links {
    display: none;
  }

  .nav-mobile-btn {
    display: flex;
  }

  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: #ffffff !important;
    padding: 24px;
    gap: 16px;
    box-shadow: var(--shadow-md);
    z-index: 9999;
    opacity: 1 !important;
    visibility: visible !important;
  }

  .nav-links.open a {
    color: var(--text) !important;
    font-size: 0.95rem;
  }

  .nav.open-menu .nav-links.open {
    background: #ffffff !important;
  }

  .nav.open-menu .nav-links.open a {
    color: var(--text) !important;
  }

  .nav.nav--scrolled .nav-links.open {
    background: #ffffff !important;
    opacity: 1 !important;
    visibility: visible !important;
  }

  .nav.nav--scrolled .nav-links.open a {
    color: var(--text) !important;
  }

  .section {
    padding: 64px 0;
  }

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

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

  .eight-adv-grid {
    grid-template-columns: 1fr;
  }

  .adv-item {
    border-right: none;
    padding: 32px 24px;
  }

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

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

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

  /* 培训教育模块响应式 */
  .training-grid {
    grid-template-columns: 1fr !important;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-title {
    font-size: 2rem;
  }

  .section-head {
    margin-bottom: 40px;
  }

  .nav-logo {
    font-size: 0.92rem;
    gap: 8px;
  }

  .nav-logo-text {
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
}

/* ========== BACK TO TOP ========== */
.back-to-top {
  position: fixed;
  right: 20px;
  bottom: 28px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(180deg, var(--primary-light), rgba(90, 126, 164, 0.9));
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 6px 18px rgba(16, 30, 50, 0.12);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.06);
  z-index: 2000;
  opacity: 0;
  transform: translateY(10px);
  transition:
    opacity 0.25s ease,
    transform 0.25s ease,
    background 0.2s ease;
  font-size: 0.95rem;
  line-height: 1;
}

.back-to-top.show {
  opacity: 1;
  transform: translateY(0);
}

.back-to-top:focus {
  outline: 2px solid rgba(255, 255, 255, 0.12);
}

@media (max-width: 768px) {
  .back-to-top {
    right: 14px;
    bottom: 18px;
    width: 42px;
    height: 42px;
  }
}