/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary: #E8452D;
      --primary-hover: #C0392B;
      --secondary: #1C1C1E;
      --accent: #F5A623;
      --bg-warm: #F7F5F2;
      --card-bg: #FFFFFF;
      --text-main: #2D2D2F;
      --text-muted: #6B6B6F;
      --text-light: #FFFFFF;
      --shadow-sm: 0 2px 16px rgba(0, 0, 0, 0.06);
      --shadow-md: 0 8px 28px rgba(0, 0, 0, 0.12);
      --shadow-nav: 0 2px 20px rgba(0, 0, 0, 0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", "SF Pro Display", sans-serif;
      --container-max: 1200px;
      --nav-height: 72px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    /* 容器 */
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* 板块通用间距 */
    section {
      padding: 80px 0;
    }

    /* 标题层级 */
    h2 {
      font-size: 36px;
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--secondary);
    }

    h3 {
      font-size: 22px;
      font-weight: 600;
      line-height: 1.4;
      margin-bottom: 8px;
    }

    .section-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 48px;
      max-width: 700px;
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: all 0.3s ease;
      border: 2px solid transparent;
      line-height: 1.2;
      text-align: center;
    }

    .btn-primary {
      background-color: var(--primary);
      color: var(--text-light);
      border-color: var(--primary);
    }

    .btn-primary:hover {
      background-color: var(--primary-hover);
      border-color: var(--primary-hover);
      transform: scale(1.03);
      box-shadow: 0 6px 18px rgba(232, 69, 45, 0.3);
    }

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

    .btn-outline:hover {
      background: var(--primary);
      color: var(--text-light);
      transform: scale(1.03);
    }

    .btn-white {
      background: white;
      color: var(--primary);
      border-color: white;
    }

    .btn-white:hover {
      background: #f0f0f0;
      border-color: #f0f0f0;
      transform: scale(1.03);
    }

    /* ----- 导航 (白底平台导航) ----- */
    #header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: white;
      height: var(--nav-height);
      display: flex;
      align-items: center;
      transition: box-shadow 0.3s ease;
    }

    #header.scrolled {
      box-shadow: var(--shadow-nav);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
    }

    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 6px;
      white-space: nowrap;
    }
    .logo i {
      font-size: 24px;
      color: var(--accent);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }

    .nav-menu a {
      font-weight: 500;
      color: var(--text-main);
      position: relative;
      padding: 8px 0;
      font-size: 16px;
    }

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

    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 3px;
      background: var(--primary);
      transition: width 0.25s ease;
    }

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

    .nav-cta {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--text-main);
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 0;
        left: -100%;
        width: 80%;
        max-width: 320px;
        height: 100vh;
        background: white;
        flex-direction: column;
        padding: 100px 30px 30px;
        gap: 24px;
        box-shadow: 2px 0 20px rgba(0,0,0,0.1);
        transition: left 0.3s ease;
        z-index: 999;
      }
      .nav-menu.open {
        left: 0;
      }
      .menu-toggle {
        display: block;
        z-index: 1001;
      }
      .nav-cta .btn {
        padding: 10px 18px;
        font-size: 14px;
      }
    }

    /* ----- Hero 首屏 ----- */
    #hero {
      height: 100vh;
      min-height: 600px;
      display: flex;
      align-items: center;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      position: relative;
      color: white;
    }
    #hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(28,28,30,0.85) 0%, rgba(28,28,30,0.4) 100%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 700px;
    }
    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 24px;
      color: white;
    }
    .hero-content p {
      font-size: 18px;
      opacity: 0.9;
      margin-bottom: 36px;
      max-width: 600px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    @media (max-width: 768px) {
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-content {
        text-align: center;
      }
      .hero-buttons {
        justify-content: center;
      }
    }

    /* 品牌价值主张 */
    .value-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
      margin-top: 20px;
    }
    .value-item i {
      font-size: 36px;
      color: var(--primary);
      margin-bottom: 12px;
    }
    .value-item h3 {
      font-size: 20px;
    }
    @media (max-width: 768px) {
      .value-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    /* 核心服务 2x3 非对称网格 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px 24px;
      margin-top: 20px;
    }
    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .service-icon {
      width: 48px;
      height: 48px;
      background: var(--bg-warm);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    .service-card h3 {
      margin-bottom: 8px;
    }
    .service-card p {
      color: var(--text-muted);
      margin-bottom: 16px;
      flex: 1;
    }
    .service-link {
      font-weight: 600;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    @media (max-width: 1024px) {
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 768px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 数据优势深色区块 */
    #advantages {
      background: var(--secondary);
      color: white;
      text-align: center;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      margin-top: 20px;
    }
    .stat-number {
      font-family: var(--font-number);
      font-size: 56px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.1;
    }
    .stat-label {
      font-size: 14px;
      opacity: 0.8;
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .stat-number {
        font-size: 40px;
      }
    }

    /* 案例横向滚动卡片 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      flex: 0 0 300px;
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s;
      scroll-snap-align: start;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .case-img {
      height: 180px;
      background: #ddd;
      overflow: hidden;
    }
    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .case-info {
      padding: 20px;
    }
    .case-tags {
      display: flex;
      gap: 8px;
      margin-top: 8px;
    }
    .tag {
      background: #f0f0f0;
      padding: 4px 10px;
      border-radius: 20px;
      font-size: 12px;
      color: var(--text-muted);
    }

    /* 流程步骤 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      position: relative;
      margin-top: 40px;
    }
    .step {
      text-align: center;
      flex: 1;
      position: relative;
    }
    .step-number {
      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: 0 auto 16px;
      position: relative;
      z-index: 2;
    }
    .step::after {
      content: '';
      position: absolute;
      top: 24px;
      left: 70%;
      width: 60%;
      height: 2px;
      background: #ddd;
      z-index: 1;
    }
    .step:last-child::after {
      display: none;
    }
    @media (max-width: 768px) {
      .process-steps {
        flex-direction: column;
        gap: 32px;
      }
      .step::after {
        display: none;
      }
    }

    /* FAQ 手风琴 */
    .faq-item {
      background: var(--bg-warm);
      border-radius: 8px;
      margin-bottom: 8px;
      overflow: hidden;
    }
    .faq-question {
      padding: 18px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: var(--bg-warm);
    }
    .faq-answer {
      padding: 0 24px 16px;
      color: var(--text-muted);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
      background: white;
    }
    .faq-item.active .faq-question {
      background: white;
    }

    /* CTA 区块 */
    #cta {
      background: linear-gradient(135deg, #E8452D, #1C1C1E);
      color: white;
      text-align: center;
    }

    /* 页脚 */
    footer {
      background: var(--secondary);
      color: #ccc;
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-size: 20px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    .footer-links a {
      display: block;
      margin-bottom: 8px;
      color: #aaa;
    }
    .footer-links a:hover {
      color: var(--accent);
    }
    .social-icons i {
      font-size: 20px;
      margin-right: 16px;
      color: #aaa;
      transition: color 0.2s;
    }
    .social-icons i:hover {
      color: var(--accent);
    }
    .copyright {
      border-top: 1px solid #333;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 12px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }