/* === 中赛新能微官网 — 响应式样式 === */

/* 平板及以上 (≥768px) */
@media (min-width: 768px) {
  :root {
    --nav-height: 64px;
    --container-padding: 24px;
  }

  .section {
    padding: var(--spacing-4xl) 0;
  }

  .section__title {
    font-size: var(--font-size-3xl);
  }

  /* 网格 */
  .grid-2 { grid-template-columns: 1fr 1fr; }
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }

  /* Hero */
  .hero__title {
    font-size: var(--font-size-5xl);
  }

  .hero__subtitle {
    font-size: var(--font-size-xl);
  }

  .hero__cta {
    flex-direction: row;
    justify-content: center;
  }

  /* 导航 - 桌面端水平菜单 */
  .nav-bar__toggle {
    display: none;
  }

  .nav-bar__menu {
    position: static;
    width: auto;
    height: auto;
    background: none;
    padding: 0;
    transform: none;
    box-shadow: none;
    display: flex;
    gap: var(--spacing-lg);
  }

  .nav-bar__link {
    padding: var(--spacing-xs) 0;
    font-size: var(--font-size-sm);
    border-bottom: none;
    color: var(--color-gray-300);
    position: relative;
  }

  .nav-bar__link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-gold-400);
    transition: width var(--transition-base);
  }

  .nav-bar__link:hover::after,
  .nav-bar__link.active::after {
    width: 100%;
  }

  .nav-bar__link.active {
    color: var(--color-gold-400);
  }

  .nav-bar__overlay {
    display: none;
  }

  .u-hidden-mobile {
    display: block;
  }

  /* 品类卡片 */
  .category-grid {
    grid-template-columns: 1fr 1fr;
  }

  /* 产品卡片 */
  .product-grid {
    grid-template-columns: 1fr 1fr;
  }

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

  /* 服务案例合作伙伴 */
  .partner-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }

  .partner-item__logo {
    aspect-ratio: 1 / 1;
  }

  /* 证书 */
  .certificate-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  /* 关于我们 - 简介两列 */
  .about__intro {
    grid-template-columns: 1fr 1fr;
  }

  /* Footer */
  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr;
  }

  /* 时间线交替布局 */
  .timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }

  .timeline__item {
    width: 50%;
    padding-left: 0;
  }

  .timeline__item:nth-child(odd) {
    padding-right: 48px;
    text-align: right;
  }

  .timeline__item:nth-child(even) {
    margin-left: 50%;
    padding-left: 48px;
  }

  .timeline__item:nth-child(odd) .timeline__dot {
    left: auto;
    right: -9px;
  }

  .timeline__item:nth-child(even) .timeline__dot {
    left: -9px;
  }
}

/* 桌面端 (≥1024px) */
@media (min-width: 1024px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }

  .hero__title {
    font-size: 3.5rem;
  }

  .category-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .product-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .cases-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .partner-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .stats__grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* 宽屏 (>1280px) */
@media (min-width: 1280px) {
  .container {
    padding: 0;
  }
}

/* 小屏手机优化 (<375px) */
@media (max-width: 374px) {
  .hero__title {
    font-size: var(--font-size-3xl);
  }

  .hero__subtitle {
    font-size: var(--font-size-base);
  }

  .grid-4 {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
  }
}