/* roulang page: index */
/* ===== 设计变量与基础重置 ===== */
    :root {
      --primary: #0B2B1F;
      --primary-hover: #051A12;
      --secondary: #E85D04;
      --secondary-hover: #C14A00;
      --accent: #FAA307;
      --bg-warm: #F9FAF7;
      --white: #FFFFFF;
      --dark-bg: #1E1E1E;
      --gray-border: #E5E7EB;
      --gray-light: #F3F4F6;
      --text-dark: #1F2937;
      --text-muted: #6B7280;
      --text-light: #9CA3AF;
      --shadow-sm: 0 4px 6px -1px rgba(0,0,0,0.1);
      --shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.15);
      --radius-lg: 16px;
      --radius-full: 50px;
      --max-width: 1280px;
      --header-height: 72px;
      --transition: 0.25s ease;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-dark);
      line-height: 1.6;
      font-size: 16px;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      transition: background 0.2s;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    button, input, textarea {
      font-family: inherit;
    }

    ul {
      list-style: none;
      padding: 0;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    /* ===== 导航系统 (白底固顶) ===== */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(8px);
      z-index: 100;
      display: flex;
      align-items: center;
      border-bottom: 1px solid transparent;
      transition: box-shadow var(--transition), border-color var(--transition);
    }

    .site-header.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.05);
      border-bottom: 1px solid rgba(0,0,0,0.05);
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      display: flex;
      align-items: center;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
      letter-spacing: -0.5px;
    }

    .logo i {
      font-size: 2rem;
      margin-right: 8px;
      color: var(--secondary);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-links a {
      font-weight: 500;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
      font-size: 1rem;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--secondary);
      transition: width var(--transition);
    }

    .nav-links a:hover {
      color: var(--secondary);
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-full);
      font-weight: 600;
      font-size: 0.95rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
      border: none;
      cursor: pointer;
      white-space: nowrap;
    }

    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-2px);
      box-shadow: var(--shadow-sm);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-full);
      font-weight: 600;
      font-size: 0.95rem;
      transition: all 0.2s;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
    }

    .btn-outline:hover {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
      transform: translateY(-2px);
    }

    .mobile-toggle {
      display: none;
      font-size: 1.8rem;
      color: var(--primary);
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }

    .mobile-menu {
      display: none;
    }

    /* 移动端全屏菜单 */
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .mobile-toggle { display: block; }
      .mobile-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--primary);
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 32px;
        z-index: 110;
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.3s;
      }
      .mobile-menu.active {
        opacity: 1;
        pointer-events: auto;
      }
      .mobile-menu a {
        color: white;
        font-size: 1.5rem;
        font-weight: 600;
      }
      .close-menu {
        position: absolute;
        top: 24px;
        right: 24px;
        background: none;
        border: none;
        color: white;
        font-size: 2rem;
      }
    }

    /* ===== Hero 首屏 ===== */
    .hero {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-color: #0B2B1F; /* 后备色 */
      position: relative;
      padding: 160px 0 100px;
      margin-top: var(--header-height);
      color: white;
      overflow: hidden;
    }

    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(11,43,31,0.8) 0%, rgba(11,43,31,0.7) 100%);
    }

    .hero-content {
      position: relative;
      display: flex;
      align-items: center;
      gap: 60px;
      flex-wrap: wrap;
      z-index: 2;
    }

    .hero-text {
      flex: 1 1 500px;
    }

    .hero h1 {
      font-size: 3.25rem;
      font-weight: 800;
      line-height: 1.15;
      margin-bottom: 1.2rem;
      letter-spacing: -0.5px;
    }

    .hero .subtitle {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.85);
      margin-bottom: 2rem;
      max-width: 500px;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .hero-image {
      flex: 0 0 320px;
      filter: drop-shadow(0 20px 25px rgba(0,0,0,0.4));
      display: flex;
      align-items: center;
    }

    .hero-image img {
      width: 100%;
      height: auto;
      border-radius: 24px;
      background: rgba(255,255,255,0.1);
      backdrop-filter: blur(6px);
    }

    @media (max-width: 768px) {
      .hero { padding: 140px 0 80px; }
      .hero h1 { font-size: 2.125rem; }
      .hero-image { flex: 0 0 240px; margin: 0 auto; }
    }

    /* ===== 通用板块 ===== */
    .section {
      padding: 5rem 0;
    }

    .section-title {
      font-size: 2.25rem;
      font-weight: 700;
      margin-bottom: 1rem;
      text-align: center;
    }

    .section-desc {
      color: var(--text-muted);
      text-align: center;
      max-width: 650px;
      margin: 0 auto 3rem;
    }

    /* 优势卡片 (三列运动剪影风格) */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }

    .advantage-card {
      background: var(--white);
      border-radius: var(--radius-lg);
      border: 1px solid var(--gray-border);
      padding: 2.5rem 1.8rem 1.5rem;
      position: relative;
      transition: box-shadow var(--transition), transform var(--transition);
      overflow: hidden;
    }

    .advantage-card::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 4px;
      background: linear-gradient(90deg, var(--secondary), var(--accent));
      transform: translateY(4px);
      transition: transform 0.3s;
    }

    .advantage-card:hover {
      box-shadow: var(--shadow-lg);
      transform: translateY(-6px);
    }

    .advantage-card:hover::after {
      transform: translateY(0);
    }

    .icon-circle {
      width: 60px;
      height: 60px;
      background: var(--secondary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.4rem;
      color: white;
      font-size: 2rem;
    }

    .advantage-card h3 {
      font-size: 1.4rem;
      font-weight: 600;
      margin-bottom: 0.6rem;
    }

    .advantage-card p {
      color: var(--text-muted);
      margin-bottom: 1.5rem;
      font-size: 0.95rem;
    }

    .text-link {
      color: var(--secondary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: gap 0.2s;
    }

    .text-link i { font-size: 0.8rem; }
    .text-link:hover { gap: 10px; text-decoration: underline; }

    /* 产品/服务卡片 (两列交替) */
    .product-row {
      display: flex;
      gap: 40px;
      align-items: center;
      margin-bottom: 4rem;
      flex-wrap: wrap;
    }

    .product-row.reverse {
      flex-direction: row-reverse;
    }

    .product-img {
      flex: 1 1 45%;
      border-radius: var(--radius-lg);
      overflow: hidden;
    }

    .product-img img {
      width: 100%;
      height: auto;
      border-radius: var(--radius-lg);
      transition: transform 0.3s;
    }

    .product-img:hover img {
      transform: scale(1.02);
    }

    .product-info {
      flex: 1 1 45%;
    }

    .product-info h3 {
      font-size: 1.7rem;
      font-weight: 600;
      margin-bottom: 0.8rem;
    }

    .feature-list {
      margin-top: 1rem;
    }

    .feature-list li {
      display: flex;
      align-items: baseline;
      gap: 8px;
      margin-bottom: 0.5rem;
      color: var(--text-dark);
    }

    .feature-list i {
      color: var(--secondary);
      font-size: 0.7rem;
    }

    /* 案例数据深色块 */
    .case-stats {
      background: var(--dark-bg);
      color: white;
      padding: 3.5rem 0;
    }

    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
      text-align: center;
    }

    .stat-number {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--accent);
      margin-bottom: 8px;
    }

    .stat-label {
      color: rgba(255,255,255,0.75);
      font-size: 0.95rem;
    }

    /* FAQ 手风琴 */
    .faq-list {
      max-width: 780px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .faq-item {
      background: var(--white);
      border-radius: 12px;
      border: 1px solid var(--gray-border);
    }

    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 18px 24px;
      text-align: left;
      font-size: 1rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-dark);
    }

    .faq-icon {
      color: var(--secondary);
      font-size: 1.3rem;
      transition: transform 0.2s;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      background: var(--gray-light);
    }

    .faq-item.active .faq-answer {
      max-height: 220px;
      padding: 0 24px 24px;
    }

    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    .faq-answer p {
      padding-top: 12px;
      color: var(--text-dark);
      font-size: 0.95rem;
    }

    /* 最终CTA横幅 */
    .cta-banner {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 4.5rem 1.5rem;
    }

    .cta-banner h2 {
      font-size: 2.4rem;
      font-weight: 700;
      margin-bottom: 1rem;
    }

    .cta-btn {
      background: var(--secondary);
      color: white;
      padding: 16px 44px;
      font-size: 1.2rem;
      border-radius: var(--radius-full);
      font-weight: 700;
      margin-top: 1.8rem;
      display: inline-block;
      border: none;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
    }

    .cta-btn:hover {
      background: var(--secondary-hover);
      transform: scale(1.04);
    }

    /* 页脚 */
    .site-footer {
      background: var(--dark-bg);
      color: #E5E7EB;
      padding: 3.5rem 0 1.8rem;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      margin-bottom: 2.5rem;
    }

    .footer-grid h5 {
      font-size: 1rem;
      font-weight: 700;
      margin-bottom: 1.2rem;
      color: white;
    }

    .footer-links a {
      display: block;
      color: var(--text-light);
      margin-bottom: 0.8rem;
      font-size: 0.9rem;
    }

    .footer-links a:hover { color: var(--secondary); }

    .copyright {
      border-top: 1px solid rgba(255,255,255,0.15);
      padding-top: 1.6rem;
      text-align: center;
      font-size: 0.9rem;
      color: var(--text-light);
    }

    @media (max-width: 768px) {
      .advantages-grid, .stats-grid, .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .product-row { flex-direction: column; }
      .product-row.reverse { flex-direction: column; }
    }

    @media (max-width: 520px) {
      .advantages-grid, .stats-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .hero-buttons .btn-primary,
      .hero-buttons .btn-outline {
        width: 100%;
      }
    }