/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary: #0A1F3F;
      --primary-hover: #081830;
      --accent: #E8380D;
      --accent-glow: #FF4A1A;
      --bg: #F5F7FA;
      --card-bg: #FFFFFF;
      --text-main: #1A1A1A;
      --text-soft: #5A6B7F;
      --text-footer: #B0BECC;
      --success: #00B578;
      --disable: #C0C8D4;
      --border-light: #E0E5EC;
      --border-input: #D0D7E2;
      --shadow-sm: 0 4px 20px rgba(10,31,63,0.06);
      --shadow-md: 0 8px 30px rgba(10,31,63,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, sans-serif;
      --max-width: 1200px;
      --gap: 24px;
    }

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

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

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

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

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

    button, input, textarea {
      font-family: inherit;
    }

    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.3;
    }

    h1 {
      font-size: 36px;
      color: var(--primary);
    }

    h2 {
      font-size: 28px;
      color: var(--primary);
      margin-bottom: 40px;
      text-align: center;
      position: relative;
    }

    h2::after {
      content: '';
      display: block;
      width: 60px;
      height: 4px;
      background: var(--accent);
      margin: 14px auto 0;
      border-radius: 2px;
    }

    h3 {
      font-size: 20px;
      font-weight: 600;
      color: #1A1A1A;
    }

    h4 {
      font-size: 18px;
      font-weight: 600;
      color: #1A1A1A;
    }

    .section {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      h1 {
        font-size: 28px;
      }
      h2 {
        font-size: 24px;
      }
    }

    /* ----- 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;
      cursor: pointer;
      border: none;
      transition: var(--transition);
      text-align: center;
    }

    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }

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

    .btn-accent {
      background: var(--accent);
      color: white;
      box-shadow: 0 0 12px rgba(232,56,13,0.2);
    }
    .btn-accent:hover {
      background: var(--accent-glow);
      box-shadow: 0 0 20px rgba(232,56,13,0.4);
      transform: translateY(-2px);
    }

    /* ----- 导航系统 ----- */
    .main-header {
      background: white;
      position: sticky;
      top: 0;
      z-index: 1000;
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 16px 20px;
      max-width: var(--max-width);
      margin: 0 auto;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      font-size: 28px;
      color: var(--accent);
    }

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

    .nav-links a {
      font-weight: 500;
      color: var(--text-main);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: var(--transition);
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }

    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 26px;
      color: var(--primary);
      cursor: pointer;
    }

    @media (max-width: 1024px) {
      .nav-links {
        gap: 20px;
      }
    }

    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: white;
        flex-direction: column;
        padding: 100px 30px 40px;
        gap: 28px;
        box-shadow: -5px 0 25px rgba(0,0,0,0.1);
        transition: 0.3s ease;
        z-index: 999;
      }
      .nav-links.open {
        right: 0;
      }
      .mobile-toggle {
        display: block;
        z-index: 1001;
      }
      .nav-links a {
        font-size: 20px;
      }
    }

    /* ----- Hero 首屏 ----- */
    .hero {
      background: linear-gradient(135deg, rgba(10,31,63,0.92) 0%, rgba(10,31,63,0.7) 100%), 
                  url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      color: white;
      padding: 120px 0 100px;
      display: flex;
      align-items: center;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 50px;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      color: white;
      font-size: 42px;
      margin-bottom: 20px;
      text-shadow: 0 2px 10px rgba(0,0,0,0.3);
    }
    .hero-text p {
      font-size: 18px;
      color: rgba(255,255,255,0.9);
      margin-bottom: 30px;
      max-width: 500px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      flex: 1;
      display: flex;
      justify-content: center;
    }
    .hero-visual img {
      max-height: 320px;
      border-radius: 16px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.4);
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-text h1 {
        font-size: 30px;
      }
      .hero-actions {
        justify-content: center;
      }
    }

    /* ----- 卡片系统 ----- */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }

    .features-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: var(--gap);
      margin-top: 20px;
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      background: rgba(10,31,63,0.08);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--accent);
      font-size: 24px;
      margin-bottom: 16px;
    }

    @media (max-width: 1024px) {
      .features-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 520px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 场景交替布局 */
    .scene-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .scene-row.reverse {
      flex-direction: row-reverse;
    }
    .scene-img {
      flex: 1;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .scene-content {
      flex: 1;
    }
    @media (max-width: 768px) {
      .scene-row, .scene-row.reverse {
        flex-direction: column;
        gap: 30px;
      }
    }

    /* 案例数据墙 */
    .cases-wall {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: var(--gap);
    }
    .case-stat {
      background: white;
      padding: 24px;
      border-radius: var(--radius-card);
      text-align: center;
      box-shadow: var(--shadow-sm);
    }
    .case-stat .number {
      font-size: 36px;
      font-weight: 700;
      color: var(--accent);
    }
    @media (max-width: 768px) {
      .cases-wall {
        grid-template-columns: repeat(2,1fr);
      }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s ease;
      color: var(--text-soft);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    /* 页脚 */
    .footer {
      background: var(--primary);
      color: var(--text-footer);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 2fr;
      gap: 40px;
    }
    .footer-form input, .footer-form textarea {
      width: 100%;
      padding: 12px;
      margin-bottom: 12px;
      border-radius: var(--radius-btn);
      border: 1px solid var(--border-input);
      background: white;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 结构化数据隐藏 */
    .sr-only {
      position: absolute;
      width: 1px;
      height: 1px;
      padding: 0;
      margin: -1px;
      overflow: hidden;
    }