/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-dark: #3A54D4;
      --primary-light: rgba(78,110,242,0.08);
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --text: #1F2329;
      --text-secondary: #86909C;
      --text-light: #A8B0BF;
      --border-light: #E9EBF0;
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.02);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.08), 0 4px 8px rgba(0,0,0,0.04);
      --radius-sm: 8px;
      --radius: 12px;
      --radius-xl: 20px;
      --radius-pill: 50px;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
      --spacing-xs: 8px;
      --spacing-sm: 16px;
      --spacing-md: 24px;
      --spacing-lg: 40px;
      --spacing-xl: 80px;
      --spacing-2xl: 120px;
      --max-width: 1200px;
      --header-height: 72px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      text-rendering: optimizeLegibility;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.2s ease;
    }

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

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: var(--surface);
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
      z-index: 100;
      display: flex;
      align-items: center;
    }

    .header .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--text);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      gap: var(--spacing-lg);
      align-items: center;
    }

    .nav-links a {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text);
      padding: 6px 0;
      border-bottom: 2px solid transparent;
      transition: border-color 0.2s, color 0.2s;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }

    .nav-cta {
      background: var(--primary);
      color: white !important;
      padding: 10px 24px !important;
      border-radius: var(--radius-sm);
      font-weight: 600;
      border: none !important;
      transition: background 0.2s;
    }
    .nav-cta:hover {
      background: var(--primary-dark);
      color: white !important;
    }

    .mobile-toggle {
      display: none;
      font-size: 1.8rem;
      color: var(--text);
      background: none;
      border: none;
    }

    /* 首屏 */
    .hero {
      padding: calc(var(--header-height) + 60px) 0 80px;
      background: var(--surface);
      display: flex;
      align-items: center;
      min-height: 90vh;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      font-size: clamp(2.4rem, 5vw, 3.2rem);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 1.5rem;
      color: var(--text);
    }
    .hero-content h1 span {
      color: var(--primary);
    }
    .hero-content p {
      font-size: 1.15rem;
      color: var(--text-secondary);
      margin-bottom: 2rem;
      max-width: 500px;
    }
    .hero-image {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-xl);
      min-height: 380px;
      box-shadow: var(--shadow-card);
    }

    .btn-primary {
      background: var(--primary);
      color: #fff;
      font-weight: 600;
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      font-size: 1rem;
      box-shadow: 0 8px 18px rgba(78,110,242,0.25);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-1px);
      box-shadow: 0 12px 24px rgba(78,110,242,0.3);
    }

    .section {
      padding: var(--spacing-2xl) 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 50px;
    }
    .section-title h2 {
      font-size: 2rem;
      font-weight: 700;
      color: var(--text);
    }
    .section-title p {
      color: var(--text-secondary);
      margin-top: 10px;
    }

    /* 服务 cards 2x2 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 28px;
    }
    .service-card {
      background: var(--surface);
      padding: 32px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-card);
      display: flex;
      gap: 20px;
      align-items: flex-start;
      transition: all 0.25s;
    }
    .service-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .service-icon {
      font-size: 2.4rem;
      color: var(--primary);
      background: var(--primary-light);
      width: 64px;
      height: 64px;
      border-radius: var(--radius);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .service-text h3 {
      font-size: 1.4rem;
      font-weight: 650;
      margin-bottom: 8px;
    }
    .service-text p {
      color: var(--text-secondary);
      line-height: 1.5;
    }

    /* 优势数据深色块 */
    .advantages {
      background: #1F2329;
      color: white;
      padding: 80px 0;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
      text-align: center;
    }
    .stat-item .stat-number {
      font-size: 3.2rem;
      font-weight: 700;
      color: var(--primary);
      line-height: 1.2;
    }
    .stat-item .stat-label {
      color: #B0B8C9;
      margin-top: 8px;
      font-size: 1rem;
    }

    /* 案例卡片 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .case-card {
      background: var(--surface);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: all 0.25s;
    }
    .case-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .case-tag {
      position: absolute;
      top: 16px;
      left: 16px;
      background: var(--orange);
      color: #fff;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 0.75rem;
      font-weight: 600;
    }
    .case-body {
      padding: 20px;
    }
    .case-body h3 {
      font-weight: 650;
      margin-bottom: 8px;
    }
    .case-body p {
      color: var(--text-secondary);
      font-size: 0.9rem;
    }

    /* 流程步骤 */
    .steps-row {
      display: flex;
      justify-content: space-between;
      gap: 30px;
    }
    .step {
      flex: 1;
      text-align: center;
      position: relative;
    }
    .step-circle {
      width: 80px;
      height: 80px;
      background: var(--primary-light);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 20px;
      font-size: 2rem;
      color: var(--primary);
      font-weight: 700;
    }
    .step h4 {
      font-weight: 650;
    }
    .step p {
      color: var(--text-secondary);
      font-size: 0.9rem;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius);
      margin-bottom: 16px;
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: white;
      border: none;
      width: 100%;
      font-size: 1.05rem;
    }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-secondary);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    .cta-section {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 80px 0;
      border-radius: var(--radius-xl);
      margin: 60px 0;
    }
    .cta-section h2 {
      font-size: 2.3rem;
      font-weight: 700;
    }
    .btn-white {
      background: white;
      color: var(--primary);
      font-weight: 700;
      padding: 14px 38px;
      border-radius: var(--radius-sm);
      margin-top: 24px;
    }

    /* Footer */
    .footer {
      background: #1F2329;
      color: #B0B8C9;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      color: white;
      font-size: 1.6rem;
      font-weight: 700;
    }
    .footer a {
      color: #B0B8C9;
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #2E333B;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 0.9rem;
    }

    @media (max-width: 1024px) {
      .cases-grid { grid-template-columns: repeat(2,1fr); }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .mobile-toggle { display: block; }
      .hero-grid { flex-direction: column; }
      .services-grid { grid-template-columns: 1fr; }
      .cases-grid { grid-template-columns: 1fr; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .steps-row { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr; }
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 20px;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    }
    .mobile-menu.active { display: flex; }