/* ============================================
   赛弗尼（SAFEN）企业门户 - 响应式样式
   断点：1440+ / 1024-1439 / 768-1023 / <768
   ============================================ */

/* --- 大屏 >=1440px --- */
@media (min-width: 1440px) {
  :root {
    --container-width: 1320px;
  }
  
  h1 {
    font-size: 3rem;
  }
  
  h2 {
    font-size: 2.4rem;
  }
  
  .page-banner {
    height: 420px;
  }
}

/* --- 标准桌面 1024-1439px --- */
@media (max-width: 1439px) and (min-width: 1024px) {
  :root {
    --container-width: 1000px;
  }
}

/* --- 平板 768-1023px --- */
@media (max-width: 1023px) and (min-width: 768px) {
  :root {
    --container-width: 720px;
    --header-height: 70px;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.7rem;
  }
  
  .section {
    padding: var(--spacing-2xl) 0;
  }
  
  /* 导航 - 平板仍保持水平，但紧凑 */
  .nav-menu > li > a {
    padding: var(--spacing-sm) 10px;
    font-size: 0.88rem;
  }
  
  /* Footer 两列 */
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
  }
  
  .page-banner {
    height: 300px;
  }
  
  .page-banner-content h1 {
    font-size: 2rem;
  }
  
  /* 关于我们 - 企业介绍 */
  .about-intro {
    gap: var(--spacing-xl);
  }
  
  /* 资质荣誉 */
  .honor-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* --- 手机 <768px --- */
@media (max-width: 767px) {
  :root {
    --header-height: 60px;
    --spacing-3xl: 60px;
  }
  
  h1 {
    font-size: 1.75rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .section {
    padding: var(--spacing-xl) 0;
  }
  
  /* 关于我们 - 企业介绍单列 */
  .about-intro {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .about-intro-text {
    order: 1;
  }
  
  .about-intro-image {
    order: 2;
  }
  
  .about-intro .section-title {
    text-align: center;
  }
  
  .about-intro .section-title h2::before {
    left: 50%;
    transform: translateX(-50%);
  }
  
  .about-intro .section-title h2::after {
    left: 50%;
    transform: translateX(-50%);
  }
  
  /* 时间轴单列 */
  .timeline::before {
    left: 16px;
    transform: none;
  }
  
  .timeline-item,
  .timeline-item:nth-child(odd),
  .timeline-item:nth-child(even) {
    width: 100%;
    margin-left: 0;
    padding-left: 48px;
    padding-right: 0;
    text-align: left;
  }
  
  .timeline-item:nth-child(odd) .timeline-node,
  .timeline-item:nth-child(even) .timeline-node {
    left: 7px;
    right: auto;
  }
  
  /* 资质荣誉 */
  .honor-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
  }
  
  /* 团队 */
  .team-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
  
  /* 显示汉堡菜单按钮 */
  .nav-toggle {
    display: flex;
  }
  
  /* 移动端导航菜单 */
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--color-primary-dark);
    padding: var(--spacing-lg);
    gap: 0;
    overflow-y: auto;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
  }
  
  .nav-menu.open {
    transform: translateX(0);
  }
  
  .nav-menu > li > a {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    font-size: 1rem;
  }
  
  .nav-menu > li > a::after {
    display: none;
  }
  
  /* 移动端二级菜单 - 手风琴展开 */
  .nav-submenu {
    position: static;
    transform: none;
    min-width: auto;
    background: rgba(255, 255, 255, 0.03);
    border: none;
    border-top: none;
    border-left: 2px solid var(--color-accent-red);
    margin-left: var(--spacing-md);
    padding: 0;
    max-height: 0;
    overflow: hidden;
    opacity: 1;
    visibility: visible;
    transition: max-height var(--transition-normal);
    box-shadow: none;
  }
  
  .nav-submenu::before {
    display: none;
  }
  
  .nav-menu > li:hover > .nav-submenu {
    transform: none;
  }
  
  .nav-submenu.open {
    max-height: 500px;
    padding: var(--spacing-sm) 0;
  }
  
  .nav-submenu li a {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  /* 带子菜单的项显示展开箭头 */
  .nav-menu > li.has-submenu > a {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  .nav-menu > li.has-submenu > a::before {
    content: '+';
    font-size: 1.2rem;
    font-weight: var(--font-weight-bold);
    transition: transform var(--transition-fast);
  }
  
  .nav-menu > li.has-submenu.submenu-open > a::before {
    transform: rotate(45deg);
  }
  
  /* Footer 单列 */
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: var(--spacing-sm);
    text-align: center;
  }
  
  /* Banner */
  .page-banner {
    height: 240px;
  }
  
  .page-banner-content h1 {
    font-size: 1.6rem;
  }
  
  /* 按钮 */
  .btn {
    padding: 10px 20px;
    font-size: 0.9rem;
  }
  
  /* 回到顶部 */
  .back-to-top {
    bottom: 24px;
    right: 24px;
    width: 38px;
    height: 38px;
  }
  
  /* 区块标题 */
  .section-title {
    margin-bottom: var(--spacing-xl);
  }
}

/* --- 超小屏 <480px --- */
@media (max-width: 479px) {
  h1 {
    font-size: 1.5rem;
  }
  
  h2 {
    font-size: 1.3rem;
  }
  
  .page-banner {
    height: 200px;
  }
  
  .page-banner-content h1 {
    font-size: 1.4rem;
  }
  
  /* 资质荣誉单列 */
  .honor-grid {
    grid-template-columns: 1fr;
  }
}