/* roulang page: index */
:root {
      --primary: #E8451E;
      --primary-dark: #C93A18;
      --primary-light: #FFF0EC;
      --secondary: #3A5068;
      --secondary-hover: #2c3e50;
      --dark: #1E2024;
      --white: #FFFFFF;
      --bg: #FAF9F7;
      --card-bg: #FFFFFF;
      --border-light: #E8E6E1;
      --text-main: #4A4A4A;
      --text-muted: #7A7A7A;
      --text-dark: #1E2024;
      --gold: #D4A017;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.06);
      --transition: 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      background-color: var(--bg);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    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;
      outline: none;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      color: var(--text-dark);
      line-height: 1.3;
    }
    h2 {
      font-size: 2.25rem;
      margin-bottom: 0.5rem;
      letter-spacing: -0.3px;
    }
    h3 {
      font-size: 1.25rem;
      font-weight: 600;
    }
    .section {
      padding: 100px 0;
    }
    @media (max-width: 1024px) {
      .section {
        padding: 80px 0;
      }
      h2 {
        font-size: 1.9rem;
      }
    }
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      h2 {
        font-size: 1.7rem;
      }
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.2s, box-shadow 0.2s, transform 0.2s;
      border: 2px solid var(--primary);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      border-color: var(--primary-dark);
      box-shadow: 0 0 16px rgba(232,69,30,0.35);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: 2px solid var(--primary);
      transition: 0.2s;
    }
    .btn-outline:hover {
      background: var(--primary-light);
      border-color: var(--primary-dark);
      color: var(--primary-dark);
    }
    .btn-large {
      padding: 16px 40px;
      font-size: 1.1rem;
      letter-spacing: 0.3px;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.94);
      backdrop-filter: blur(6px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.02);
      z-index: 100;
      border-bottom: 1px solid rgba(0,0,0,0.02);
    }
    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 1.7rem;
      font-weight: 800;
      letter-spacing: -0.5px;
      display: flex;
      align-items: baseline;
    }
    .logo .brand-highlight {
      color: var(--primary);
      font-style: italic;
    }
    .logo .brand-dark {
      color: var(--dark);
      margin-left: 4px;
    }
    .nav-links {
      display: flex;
      gap: 2.2rem;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-size: 0.95rem;
      font-weight: 500;
      color: #3A3A3A;
      padding: 6px 0;
      border-bottom: 2px solid transparent;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .mobile-toggle {
      display: none;
      background: none;
      font-size: 1.8rem;
      color: var(--dark);
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--bg);
        flex-direction: column;
        padding: 32px 24px;
        gap: 1.8rem;
        box-shadow: 0 12px 24px rgba(0,0,0,0.05);
      }
      .nav-links.open {
        display: flex;
      }
      .mobile-toggle {
        display: block;
      }
      .nav-cta-desktop {
        display: none;
      }
    }

    /* Hero */
    .hero {
      padding: 140px 0 80px;
      background: var(--bg);
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: "";
      position: absolute;
      top: 0;
      right: 0;
      width: 420px;
      height: 420px;
      background: radial-gradient(circle at 30% 30%, rgba(232,69,30,0.04) 0%, transparent 70%);
      border-radius: 50%;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: 3rem;
      font-weight: 800;
      line-height: 1.25;
      letter-spacing: -0.5px;
      margin-bottom: 1.2rem;
      color: var(--dark);
    }
    .hero-text .sub {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 2rem;
      max-width: 520px;
    }
    .hero-image {
      flex: 1;
      position: relative;
    }
    .hero-image img {
      border-radius: 20px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.08);
      width: 100%;
      height: auto;
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: left;
      }
      .hero-text h1 {
        font-size: 2.3rem;
      }
    }

    /* 核心优势卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .advantage-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      border: 1px solid var(--border-light);
    }
    .advantage-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: rgba(58,80,104,0.06);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--secondary);
      font-size: 1.5rem;
    }
    .advantage-card h3 {
      margin-bottom: 10px;
    }
    @media (max-width: 768px) {
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 产品功能左右交替 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 3.5rem;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-img img {
      border-radius: 16px;
      box-shadow: var(--shadow-card);
    }
    .feature-content {
      flex: 1;
    }
    .feature-list {
      list-style: none;
      margin-top: 1.2rem;
    }
    .feature-list li {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
      color: var(--text-main);
    }
    .check-icon {
      color: var(--primary);
      font-weight: bold;
    }
    @media (max-width: 768px) {
      .feature-row, .feature-row.reverse {
        flex-direction: column;
      }
    }

    /* 场景卡片 */
    .scene-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .scene-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      border: 1px solid var(--border-light);
    }
    .scene-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-hover);
    }
    .scene-card img {
      height: 180px;
      object-fit: cover;
    }
    .scene-info {
      padding: 20px;
    }
    @media (max-width: 768px) {
      .scene-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 数据墙 */
    .stats-band {
      display: flex;
      justify-content: space-around;
      background: var(--white);
      border-radius: 20px;
      padding: 40px 20px;
      box-shadow: var(--shadow-card);
      margin-top: 20px;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--gold);
      font-family: "DIN Alternate", "PingFang SC", sans-serif;
    }
    @media (max-width: 768px) {
      .stats-band {
        flex-direction: column;
        gap: 28px;
      }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      cursor: pointer;
      color: var(--dark);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: #5A5A5A;
      font-size: 0.95rem;
      padding-right: 20px;
    }
    .faq-item.active .faq-answer {
      max-height: 150px;
      padding-top: 12px;
    }

    /* 底部CTA */
    .cta-dark {
      background: var(--dark);
      color: white;
      text-align: center;
      padding: 80px 20px;
      border-radius: 0;
    }
    .cta-dark h2 {
      color: white;
      margin-bottom: 16px;
    }

    /* 页脚 */
    .footer {
      background: #16181b;
      color: #9A9A9A;
      font-size: 0.85rem;
      padding: 30px 24px;
    }
    .footer-content {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
    }