/* roulang page: index */
/* ----- 设计变量 & 全局重置 ----- */
    :root {
      --primary: #1B2A4A;
      --primary-hover: #152237;
      --silver: #C0C5CE;
      --gold: #F4B940;
      --gold-hover: #E0A830;
      --bg: #FAFBFD;
      --card-bg: #FFFFFF;
      --hero-gradient-start: #F0F3FA;
      --text-primary: #1E2A3B;
      --text-secondary: #6B7280;
      --border-light: #E5E7EB;
      --shadow-sm: 0 4px 20px rgba(27,42,74,0.06);
      --shadow-hover: 0 12px 28px rgba(27,42,74,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --max-width: 1200px;
      --nav-height: 64px;
      --transition: 0.25s ease;
    }

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

    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height);
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
      font-weight: 500;
    }

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

    /* 板块通用间距 */
    .section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      :root {
        --radius-card: 8px;
      }
    }

    /* ----- 导航栏 (固定白底半透明) ----- */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.04);
      z-index: 1000;
      display: flex;
      align-items: center;
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
      letter-spacing: 0.5px;
    }

    .logo-icon {
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--gold);
      font-size: 28px;
      line-height: 1;
    }

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

    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-primary);
      position: relative;
      padding: 4px 0;
    }

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

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 4px;
      transition: var(--transition);
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(12px);
        flex-direction: column;
        gap: 28px;
        padding: 40px 24px;
        transform: translateY(-120%);
        opacity: 0;
        transition: transform 0.3s ease, opacity 0.2s ease;
        box-shadow: 0 8px 24px rgba(0,0,0,0.05);
        pointer-events: none;
      }

      .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
      }

      .nav-links a {
        font-size: 18px;
      }

      .hamburger {
        display: flex;
      }
    }

    /* ----- 按钮系统 ----- */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(27,42,74,0.2);
    }

    .btn-primary:hover {
      background: var(--primary-hover);
      transform: scale(1.02);
      box-shadow: 0 8px 18px rgba(27,42,74,0.25);
    }

    .btn-outline {
      border: 1.5px solid var(--silver);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      background: transparent;
    }

    .btn-outline:hover {
      border-color: var(--primary);
      background: rgba(27,42,74,0.03);
    }

    .btn-gold {
      background: var(--gold);
      color: var(--primary);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      box-shadow: 0 6px 18px rgba(244,185,64,0.4);
    }

    .btn-gold:hover {
      background: var(--gold-hover);
      transform: scale(1.02);
    }

    .text-link {
      color: var(--primary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      border-bottom: 1.5px solid transparent;
    }

    .text-link:hover {
      border-bottom-color: var(--primary);
    }

    /* ----- 首屏 Hero ----- */
    .hero {
      padding-top: calc(var(--nav-height) + 60px);
      padding-bottom: 80px;
      background: linear-gradient(135deg, var(--hero-gradient-start) 0%, #FAFBFD 100%);
      display: flex;
      align-items: center;
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }

    .hero-content h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.35;
      color: var(--primary);
      margin-bottom: 18px;
    }

    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
    }

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

    .hero-image {
      position: relative;
      display: flex;
      justify-content: center;
    }

    .hero-image img {
      border-radius: 20px;
      box-shadow: 0 24px 48px rgba(27,42,74,0.15);
      transition: transform 0.4s ease;
    }

    .hero-image::after {
      content: '';
      position: absolute;
      width: 280px;
      height: 280px;
      background: radial-gradient(circle, rgba(244,185,64,0.2) 0%, transparent 70%);
      top: -20px;
      right: -20px;
      z-index: -1;
    }

    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .hero-content h1 {
        font-size: 28px;
      }
      .hero-image {
        order: -1;
      }
    }

    /* 卡片通用 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      padding: 24px;
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }

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

    /* 核心优势 - 大数字序号 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 40px;
      text-align: center;
    }

    .adv-item .adv-number {
      font-size: 48px;
      font-weight: 300;
      color: var(--silver);
      line-height: 1.1;
      margin-bottom: 12px;
    }

    .adv-item h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }

    .adv-item p {
      color: var(--text-secondary);
    }

    @media (max-width: 768px) {
      .advantages-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
    }

    /* 功能分组 - 左右交替 */
    .feature-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 80px;
    }

    .feature-row.reverse {
      direction: rtl;
    }

    .feature-row.reverse .feature-text {
      direction: ltr;
    }

    .feature-text h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 16px;
    }

    .feature-list {
      list-style: none;
      margin-bottom: 24px;
    }

    .feature-list li {
      display: flex;
      align-items: baseline;
      gap: 10px;
      margin-bottom: 10px;
      color: var(--text-secondary);
    }

    .feature-list li::before {
      content: '•';
      color: var(--gold);
      font-weight: bold;
    }

    .feature-image img {
      border-radius: 12px;
      box-shadow: var(--shadow-sm);
    }

    @media (max-width: 768px) {
      .feature-row, .feature-row.reverse {
        grid-template-columns: 1fr;
        gap: 32px;
        direction: ltr;
      }
      .feature-image {
        order: -1;
      }
    }

    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .scenario-card img {
      border-radius: 8px;
      height: 200px;
      object-fit: cover;
      width: 100%;
      transition: transform 0.3s;
    }

    .scenario-card:hover img {
      transform: scale(1.03);
    }

    .scenario-card h3 {
      margin: 16px 0 8px;
    }

    @media (max-width: 768px) {
      .scenarios-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 案例网格 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    .case-item {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      display: flex;
      gap: 20px;
      align-items: center;
      box-shadow: var(--shadow-sm);
    }

    .case-logo {
      width: 70px;
      height: 70px;
      background: #F0F3FA;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--text-secondary);
      font-size: 14px;
      flex-shrink: 0;
    }

    .case-data {
      font-weight: 700;
      color: var(--gold);
      font-size: 20px;
    }

    @media (max-width: 768px) {
      .cases-grid {
        grid-template-columns: 1fr;
        overflow-x: auto;
        display: flex;
        gap: 16px;
        padding-bottom: 10px;
      }
      .case-item {
        min-width: 260px;
      }
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 18px;
      font-weight: 500;
      cursor: pointer;
      width: 100%;
      text-align: left;
    }

    .faq-icon {
      font-size: 22px;
      transition: transform 0.3s;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      color: var(--text-secondary);
      padding-right: 40px;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
      padding-bottom: 8px;
    }

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

    .faq-item.active {
      background: #F7F8FC;
      padding-left: 16px;
      border-radius: 6px;
    }

    /* 全局CTA */
    .cta-banner {
      background: var(--primary);
      padding: 80px 0;
      text-align: center;
      color: white;
      position: relative;
      overflow: hidden;
    }

    .cta-banner::before {
      content: '';
      position: absolute;
      width: 400px;
      height: 400px;
      background: radial-gradient(circle, rgba(255,255,255,0.05) 0%, transparent 70%);
      top: -100px;
      right: -80px;
    }

    .cta-banner h2 {
      font-size: 30px;
      margin-bottom: 16px;
      color: white;
    }

    .cta-sub {
      color: #C0C5CE;
      margin-bottom: 32px;
    }

    /* 页脚 */
    .footer {
      background: #F0F3FA;
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }

    .footer-col h4 {
      margin-bottom: 18px;
      font-weight: 600;
    }

    .footer-col ul {
      list-style: none;
    }

    .footer-col li {
      margin-bottom: 10px;
      color: var(--text-secondary);
    }

    .copyright {
      margin-top: 40px;
      padding-top: 20px;
      border-top: 1px solid var(--border-light);
      text-align: center;
      color: var(--text-secondary);
      font-size: 14px;
    }

    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 520px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }