/* roulang page: index */
:root {
      --primary: #0A4DA4;
      --primary-light: rgba(10, 77, 164, 0.1);
      --accent: #F97316;
      --dark: #1E293B;
      --body: #475569;
      --gray-bg: #F8FAFC;
      --white: #FFFFFF;
      --success: #10B981;
      --border: #E2E8F0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-hover: 0 10px 25px rgba(0,0,0,0.08), 0 4px 10px rgba(0,0,0,0.04);
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --max-width: 1200px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background: var(--white);
      color: var(--body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s ease;
      font-weight: 600;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    /* 导航 */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--border);
      z-index: 50;
      height: 72px;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 22px;
      font-weight: 700;
      color: var(--primary);
    }
    .logo img {
      width: 36px;
      height: 36px;
      border-radius: 8px;
      object-fit: cover;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-menu a {
      font-size: 15px;
      font-weight: 500;
      color: var(--body);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: all 0.2s;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 3px;
      background: var(--dark);
      border-radius: 4px;
      transition: 0.3s;
    }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        align-items: flex-start;
        padding: 24px 32px;
        gap: 24px;
        border-bottom: 1px solid var(--border);
        transform: translateY(-120%);
        opacity: 0;
        transition: 0.3s ease;
        z-index: 49;
      }
      .nav-menu.open {
        transform: translateY(0);
        opacity: 1;
      }
      .hamburger {
        display: flex;
      }
    }
    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background: var(--white);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-text h1 {
      font-size: 48px;
      font-weight: 800;
      letter-spacing: -0.5px;
      color: var(--dark);
      margin-bottom: 20px;
      line-height: 1.2;
    }
    .hero-text p {
      font-size: 18px;
      color: #64748B;
      margin-bottom: 32px;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-size: 16px;
    }
    .btn-primary:hover {
      background: var(--accent);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-size: 16px;
    }
    .btn-outline:hover {
      background: rgba(10,77,164,0.05);
    }
    .hero-image {
      background: #F1F5F9;
      border-radius: 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-text h1 {
        font-size: 32px;
      }
      .hero-text p {
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
      }
      .hero-buttons {
        justify-content: center;
      }
      .hero-image {
        order: -1;
        max-width: 320px;
        margin: 0 auto;
      }
      #hero {
        padding: 110px 0 80px;
      }
    }
    /* 通用板块标题 */
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 36px;
      font-weight: 700;
      color: var(--dark);
      margin-bottom: 12px;
    }
    .section-title p {
      color: #64748B;
      font-size: 18px;
    }
    /* Features */
    #features {
      padding: 80px 0;
      background: var(--gray-bg);
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
      text-align: center;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      width: 64px;
      height: 64px;
      background: var(--primary-light);
      border-radius: 50%;
      margin: 0 auto 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 28px;
      color: var(--primary);
    }
    .feature-card h3 {
      font-size: 22px;
      font-weight: 600;
      color: var(--dark);
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
      .section-title h2 {
        font-size: 26px;
      }
    }
    /* Services */
    #services {
      padding: 80px 0;
    }
    .service-row {
      display: grid;
      grid-template-columns: 40% 60%;
      gap: 48px;
      align-items: center;
      margin-bottom: 48px;
    }
    .service-row:last-child {
      margin-bottom: 0;
    }
    .service-img img {
      border-radius: 12px;
      box-shadow: var(--shadow-card);
      width: 100%;
    }
    .service-content h3 {
      font-size: 26px;
      font-weight: 600;
      color: var(--dark);
      margin-bottom: 16px;
    }
    .service-list {
      list-style: none;
      margin-top: 20px;
    }
    .service-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
      color: var(--body);
    }
    .service-list li::before {
      content: "✓";
      color: var(--success);
      font-weight: bold;
      font-size: 18px;
    }
    @media (max-width: 768px) {
      .service-row {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .service-list li {
        justify-content: center;
      }
    }
    /* Stats */
    #stats {
      padding: 80px 0;
      background: var(--gray-bg);
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .stat-number {
      font-size: 42px;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .stat-label {
      font-size: 14px;
      color: #64748B;
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    /* Process */
    #process {
      padding: 80px 0;
    }
    .process-steps {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      position: relative;
    }
    .step {
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      flex: 1;
      position: relative;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 20px;
      margin-bottom: 16px;
      z-index: 2;
    }
    .step h4 {
      font-weight: 600;
      color: var(--dark);
      margin-bottom: 6px;
    }
    .step p {
      font-size: 14px;
      color: #64748B;
    }
    .process-line {
      position: absolute;
      top: 24px;
      left: 50%;
      width: 100%;
      height: 2px;
      background: var(--border);
      z-index: 1;
    }
    @media (max-width: 768px) {
      .process-steps {
        flex-direction: column;
        gap: 32px;
        align-items: center;
      }
      .process-line {
        display: none;
      }
    }
    /* FAQ */
    #faq {
      padding: 80px 0;
      background: var(--white);
    }
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      width: 100%;
      background: transparent;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      color: var(--dark);
      display: flex;
      justify-content: space-between;
      align-items: center;
      text-align: left;
    }
    .faq-icon {
      font-size: 24px;
      transition: transform 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      padding: 0;
      color: var(--body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    /* CTA */
    #cta {
      padding: 80px 0;
      background: #F0F4FB;
      text-align: center;
    }
    #cta h2 {
      font-size: 36px;
      font-weight: 700;
      color: var(--dark);
      margin-bottom: 16px;
    }
    #cta p {
      color: #475569;
      margin-bottom: 32px;
    }
    /* Footer */
    #footer {
      background: #1E293B;
      color: #CBD5E1;
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      margin-bottom: 40px;
    }
    .footer-col h4 {
      color: white;
      margin-bottom: 16px;
      font-weight: 600;
    }
    .footer-col a {
      display: block;
      color: #CBD5E1;
      margin-bottom: 10px;
      font-size: 14px;
    }
    .footer-col a:hover {
      color: var(--accent);
    }
    .copyright {
      text-align: center;
      font-size: 14px;
      color: #94A3B8;
      border-top: 1px solid #334155;
      padding-top: 20px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }