/* roulang page: index */
/* ----- 设计变量与重置 ----- */
    :root {
      --primary-deep: #1A1A2E;
      --accent-red: #E63946;
      --accent-red-hover: #C1121F;
      --bg-light: #F1FAEE;
      --card-white: #FFFFFF;
      --highlight-ice: #E0F2F1;
      --dot-ice: #A8DADC;
      --text-dark: #1A1A2E;
      --text-body: #2D3748;
      --text-muted: #5A6A7A;
      --border-light: #E5E7EB;
      --border-input: #D1D5DB;
      
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", system-ui, -apple-system, sans-serif;
      
      --shadow-card: 0 4px 20px rgba(26, 26, 46, 0.06);
      --shadow-card-hover: 0 8px 30px rgba(26, 26, 46, 0.12);
      --shadow-nav: 0 2px 8px rgba(0,0,0,0.04);
      
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      
      --max-width: 1280px;
      --nav-height: 72px;
      --section-gap-desktop: 100px;
      --section-gap-mobile: 60px;
      --card-padding: 28px;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: none;
      transition: all 0.25s ease;
    }
    
    input, textarea {
      font-family: var(--font-sans);
      outline: none;
    }
    
    /* 工具类 */
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .section {
      padding: var(--section-gap-desktop) 0;
    }
    
    /* 导航系统 */
    #header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: var(--nav-height);
      display: flex;
      align-items: center;
      border-bottom: 1px solid rgba(229,229,229,0.8);
      box-shadow: var(--shadow-nav);
    }
    
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary-deep);
      letter-spacing: -0.3px;
    }
    
    .logo i {
      color: var(--accent-red);
      font-size: 2rem;
    }
    
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
      font-weight: 500;
      color: var(--text-dark);
    }
    
    .nav-links a {
      position: relative;
      padding: 4px 0;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-red);
      transition: width 0.2s;
    }
    
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    
    .btn-primary {
      background: var(--accent-red);
      color: white;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 0.95rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    
    .btn-primary:hover {
      background: var(--accent-red-hover);
      transform: translateY(-1px);
    }
    
    .btn-outline {
      border: 1.5px solid var(--primary-deep);
      color: var(--primary-deep);
      background: transparent;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
    }
    
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }
    
    .mobile-toggle {
      display: none;
      font-size: 1.8rem;
      color: var(--primary-deep);
    }
    
    /* Hero 区域 */
    #home {
      background: linear-gradient(135deg, #1A1A2E 0%, #16213E 100%);
      color: white;
      padding: 2rem 0 4rem;
    }
    
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    
    .hero-text h1 {
      font-size: 2.8rem;
      line-height: 1.25;
      font-weight: 700;
      letter-spacing: -0.5px;
      margin-bottom: 1.5rem;
    }
    
    .hero-text .subtitle {
      font-size: 1.2rem;
      opacity: 0.9;
      margin-bottom: 2.5rem;
    }
    
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    
    .hero-visual {
      position: relative;
      border-radius: 20px;
      overflow: hidden;
      background: rgba(255,255,255,0.05);
      backdrop-filter: blur(4px);
      min-height: 320px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    
    .hero-visual img {
      width: 100%;
      height: auto;
      object-fit: cover;
      opacity: 0.9;
    }
    
    .overlay-geo {
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 30%, rgba(230,57,70,0.15), transparent 70%);
    }
    
    /* 通用标题 */
    h2 {
      font-size: 2rem;
      font-weight: 600;
      color: var(--primary-deep);
      margin-bottom: 1rem;
      letter-spacing: -0.3px;
    }
    
    .section-header {
      text-align: center;
      margin-bottom: 3rem;
    }
    
    .section-header p {
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }
    
    /* 亮点网格 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    
    .highlight-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: var(--card-padding);
      box-shadow: var(--shadow-card);
      transition: all 0.2s;
      text-align: center;
    }
    
    .highlight-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    
    .icon-circle {
      width: 60px;
      height: 60px;
      background: #E0F2F1;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 1.2rem;
      color: var(--accent-red);
      font-size: 1.6rem;
    }
    
    .highlight-card h3 {
      font-size: 1.3rem;
      margin-bottom: 0.5rem;
      color: var(--primary-deep);
    }
    
    /* 案例瀑布流 */
    .cases-masonry {
      columns: 2;
      column-gap: 24px;
    }
    
    .case-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      margin-bottom: 24px;
      break-inside: avoid;
      transition: 0.2s;
    }
    
    .case-card:hover {
      box-shadow: var(--shadow-card-hover);
    }
    
    .case-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
    }
    
    .case-content {
      padding: 20px;
    }
    
    .tag {
      background: #E0F2F1;
      color: #1A3B3A;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 8px;
    }
    
    /* 方案对比表 */
    .solutions-table {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
      align-items: start;
    }
    
    .plan-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-card);
      position: relative;
      border: 1px solid transparent;
    }
    
    .plan-card.featured {
      background: #E0F2F1;
      border-color: var(--accent-red);
      transform: scale(1.02);
    }
    
    .badge-recommend {
      background: var(--accent-red);
      color: white;
      font-size: 0.75rem;
      padding: 4px 14px;
      border-radius: 20px;
      position: absolute;
      top: -12px;
      left: 50%;
      transform: translateX(-50%);
      font-weight: 600;
    }
    
    .plan-price {
      font-size: 2rem;
      font-weight: 700;
      color: var(--primary-deep);
      margin: 16px 0;
    }
    
    .feature-list {
      list-style: none;
      margin: 20px 0;
    }
    
    .feature-list li {
      margin: 12px 0;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    
    /* FAQ 手风琴 */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      padding: 4px 20px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.03);
      border-left: 3px solid var(--accent-red);
      transition: 0.2s;
    }
    
    .faq-question {
      font-weight: 600;
      padding: 18px 0;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-muted);
    }
    
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 18px;
    }
    
    /* 联系表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
    }
    
    .form-input {
      width: 100%;
      padding: 14px 16px;
      border: 1px solid var(--border-input);
      border-radius: var(--radius-btn);
      margin-bottom: 16px;
      font-size: 1rem;
    }
    
    .form-input:focus {
      border-color: var(--accent-red);
      box-shadow: 0 0 0 3px rgba(230,57,70,0.1);
    }
    
    /* 页脚 */
    #footer {
      background: #1A1A2E;
      color: #CBD5E0;
      padding: 50px 0 20px;
    }
    
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    
    @media (max-width: 1024px) {
      .hero-grid, .contact-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .cards-grid {
        grid-template-columns: 1fr 1fr;
      }
      .solutions-table {
        grid-template-columns: 1fr;
      }
    }
    
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .mobile-toggle { display: block; }
      .cards-grid, .cases-masonry { columns: 1; grid-template-columns: 1fr; }
      h1 { font-size: 2.2rem; }
      .section { padding: var(--section-gap-mobile) 0; }
    }
    
    .mobile-menu {
      position: fixed; top: 0; left: 0; width: 100%; height: 100%;
      background: rgba(26,26,46,0.97); display: flex; flex-direction: column;
      align-items: center; justify-content: center; gap: 2rem; z-index: 100;
      transform: translateX(100%); transition: 0.3s;
    }
    .mobile-menu.open { transform: translateX(0); }