/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary-lemon: #C8E600;
      --deep-gray: #1E1E1E;
      --frost-white: #F7F9F2;
      --race-red: #FF3A2D;
      --border-light: #EAEDE2;
      --text-mid: #6A6E65;
      --card-bg: #FFFFFF;
      --radius-lg: 16px;
      --radius-pill: 40px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 28px rgba(0,0,0,0.08);
      --transition-smooth: 0.25s cubic-bezier(0.25, 0.8, 0.25, 1.2);
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--frost-white);
      color: var(--text-mid);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4 {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      color: var(--deep-gray);
      margin: 0 0 20px;
      letter-spacing: -0.3px;
    }

    h1 {
      font-size: 48px;
      line-height: 1.15;
      font-weight: 700;
    }

    h2 {
      font-size: 36px;
      line-height: 1.25;
      font-weight: 600;
    }

    h3 {
      font-size: 22px;
      line-height: 1.4;
      font-weight: 600;
    }

    p, .body-text {
      font-size: 16px;
      line-height: 1.7;
      max-width: 72ch;
      color: var(--text-mid);
    }

    .small-label {
      font-size: 13px;
      font-weight: 500;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: var(--text-mid);
    }

    a {
      color: var(--deep-gray);
      text-decoration: none;
      transition: color 0.2s;
    }

    a:hover {
      color: var(--primary-lemon);
    }

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

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 按钮系统 */
    .btn {
      display: inline-block;
      font-weight: 600;
      border-radius: var(--radius-pill);
      padding: 14px 36px;
      text-align: center;
      transition: all 0.2s ease;
      cursor: pointer;
      border: none;
      font-size: 16px;
    }

    .btn-primary {
      background-color: var(--race-red);
      color: white;
      border: 2px solid var(--race-red);
    }

    .btn-primary:hover {
      background-color: #D62C1F;
      border-color: #D62C1F;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(255,58,45,0.2);
      color: white;
    }

    .btn-outline {
      background: transparent;
      color: var(--deep-gray);
      border: 2px solid var(--deep-gray);
    }

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

    .btn-white {
      background: white;
      color: var(--deep-gray);
      border: 2px solid white;
      font-weight: 600;
    }

    .btn-white:hover {
      background: transparent;
      color: white;
      border-color: white;
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 80px;
      background: rgba(247, 249, 242, 0.92);
      backdrop-filter: blur(12px);
      z-index: 100;
      border-bottom: 1px solid transparent;
      transition: all 0.3s;
    }

    .site-header.scrolled {
      border-bottom: 1px solid var(--border-light);
      box-shadow: 0 1px 8px rgba(0,0,0,0.02);
    }

    .nav-grid {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 80px;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--deep-gray);
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .logo i {
      color: var(--primary-lemon);
      font-size: 12px;
      margin-left: 2px;
    }

    .nav-menu {
      display: flex;
      list-style: none;
      gap: 32px;
      margin: 0;
    }

    .nav-menu a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-mid);
      position: relative;
      padding: 6px 0;
    }

    .nav-menu a::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: 0;
      width: 0;
      height: 2px;
      background: var(--primary-lemon);
      transition: width 0.25s ease;
    }

    .nav-menu a:hover {
      color: var(--primary-lemon);
    }

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

    .hamburger {
      display: none;
      font-size: 24px;
      background: none;
      border: none;
      color: var(--deep-gray);
    }

    /* 移动端导航 */
    .mobile-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: var(--deep-gray);
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      z-index: 200;
      transform: translateX(100%);
      transition: transform 0.4s ease;
    }

    .mobile-overlay.active {
      transform: translateX(0);
    }

    .mobile-overlay a {
      color: var(--frost-white);
      font-size: 24px;
      margin: 16px 0;
      font-weight: 500;
    }

    .close-menu {
      position: absolute;
      top: 24px;
      right: 24px;
      background: none;
      border: none;
      color: white;
      font-size: 32px;
    }

    /* 区块间距 */
    section {
      padding: 100px 0;
    }

    @media (max-width: 1024px) {
      section {
        padding: 80px 0;
      }
      h1 {
        font-size: 40px;
      }
      h2 {
        font-size: 30px;
      }
    }

    @media (max-width: 640px) {
      section {
        padding: 60px 0;
      }
      h1 {
        font-size: 32px;
      }
      h2 {
        font-size: 28px;
      }
      .btn {
        width: 100%;
        padding: 14px 24px;
      }
      .nav-menu {
        display: none;
      }
      .hamburger {
        display: block;
      }
    }

    /* Hero */
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      min-height: 90vh;
      padding-top: 40px;
    }

    .hero-image {
      background: radial-gradient(circle at 30% 40%, rgba(200,230,0,0.15) 0%, transparent 60%);
      border-radius: 40px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    .hero-image img {
      max-width: 100%;
      border-radius: 32px;
      filter: drop-shadow(0 20px 30px rgba(0,0,0,0.1));
    }

    /* 卡片通用 */
    .card {
      background: var(--card-bg);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 32px;
      transition: all 0.25s ease;
      box-shadow: var(--shadow-sm);
      height: 100%;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }

    .service-icon {
      font-size: 32px;
      color: var(--primary-lemon);
      margin-bottom: 20px;
    }

    .section-title {
      margin-bottom: 48px;
    }

    .section-title h2 {
      margin-bottom: 8px;
    }

    .decorated-label {
      font-size: 13px;
      font-weight: 600;
      color: var(--primary-lemon);
      letter-spacing: 1px;
      text-transform: uppercase;
      margin-bottom: 8px;
    }

    /* 数据优势 */
    .adv-bg {
      background-color: #F0F3EB;
    }

    .stat-number {
      font-size: 64px;
      font-weight: 700;
      color: var(--race-red);
      line-height: 1;
      margin-bottom: 12px;
      font-family: "Inter", "SF Pro Text", sans-serif;
    }

    /* 案例卡片 */
    .case-card {
      position: relative;
      border-radius: var(--radius-lg);
      overflow: hidden;
      background: var(--deep-gray);
    }

    .case-card img {
      transition: transform 0.4s ease;
      width: 100%;
      height: 240px;
      object-fit: cover;
    }

    .case-card:hover img {
      transform: scale(1.05);
    }

    .case-caption {
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      background: linear-gradient(transparent, rgba(0,0,0,0.7));
      color: white;
      padding: 24px;
    }

    /* 时间线 */
    .step-item {
      display: flex;
      gap: 24px;
      margin-bottom: 28px;
      align-items: flex-start;
    }

    .step-circle {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      border: 2px solid var(--primary-lemon);
      color: var(--deep-gray);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 18px;
      background: white;
      flex-shrink: 0;
    }

    /* FAQ */
    .accordion-title {
      font-weight: 600;
      font-size: 18px;
      background: transparent;
      border: none;
      width: 100%;
      text-align: left;
      padding: 18px 0;
      border-bottom: 1px solid var(--border-light);
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--deep-gray);
    }

    .accordion-content {
      padding: 0 0 16px 16px;
      border-left: 3px solid var(--primary-lemon);
      margin-top: 8px;
      display: none;
      color: var(--text-mid);
    }

    .accordion-item.active .accordion-content {
      display: block;
    }

    /* CTA 深色区 */
    .cta-dark {
      background: var(--deep-gray);
      color: white;
      text-align: center;
    }

    .cta-dark h2 {
      color: white;
    }

    .input-field {
      background: transparent;
      border: 1px solid rgba(255,255,255,0.3);
      border-radius: 40px;
      padding: 12px 20px;
      color: white;
      width: 100%;
      margin-bottom: 12px;
    }

    .input-field:focus {
      outline: none;
      border-color: var(--primary-lemon);
    }

    /* 页脚 */
    .site-footer {
      background: var(--deep-gray);
      color: var(--text-mid);
      padding: 60px 0 30px;
    }

    .footer-links a {
      color: #aaa;
      display: block;
      margin-bottom: 8px;
    }

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

    .copyright {
      border-top: 1px solid #333;
      margin-top: 48px;
      padding-top: 24px;
      font-size: 14px;
    }