/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --bg-deep: #0A0E27;
      --bg-panel: #0D1235;
      --bg-footer: #080B1F;
      --primary-cyan: #00E5FF;
      --primary-purple: #7B68EE;
      --text-white: #FFFFFF;
      --text-body: #B0C4DE;
      --text-muted: #6B7B8D;
      --success: #00E676;
      --warning: #FFB300;
      --error: #FF5252;
      --card-bg: rgba(255, 255, 255, 0.04);
      --card-border: rgba(0, 229, 255, 0.15);
      --card-hover-border: rgba(0, 229, 255, 0.35);
      --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
      --card-hover-shadow: 0 12px 40px rgba(0, 229, 255, 0.15);
      --glass-blur: blur(20px);
      --border-radius-lg: 16px;
      --border-radius-md: 12px;
      --border-radius-sm: 8px;
      --transition-smooth: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --max-width: 1200px;
      --header-height: 80px;
    }
    
    /* ----- reset & base ----- */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      overflow-x: hidden;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }
    
    button, input {
      font-family: inherit;
      border: none;
      outline: none;
      background: transparent;
    }
    
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* 数字/数据专用字体 */
    .data-number, .metric-value, .comparison-value {
      font-family: 'DIN Alternate', 'Roboto Mono', 'SF Mono', monospace;
      font-weight: 800;
    }
    
    /* 板块通用间距 */
    section {
      padding: 100px 0;
      position: relative;
    }
    
    @media (max-width: 768px) {
      section {
        padding: 70px 0;
      }
      .container {
        padding: 0 20px;
      }
    }
    
    /* ----- 导航面板 (卡片化玻璃导航) ----- */
    .main-header {
      position: fixed;
      top: 20px;
      left: 50%;
      transform: translateX(-50%);
      width: calc(100% - 40px);
      max-width: 1300px;
      z-index: 1000;
      background: rgba(10, 14, 39, 0.7);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border-radius: 60px;
      padding: 10px 20px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      border: 1px solid rgba(0, 229, 255, 0.18);
      box-shadow: 0 10px 30px rgba(0,0,0,0.5);
      transition: background 0.3s, border-color 0.3s;
    }
    
    .main-header.scrolled {
      background: rgba(8, 11, 31, 0.92);
      border-color: rgba(0, 229, 255, 0.3);
      box-shadow: 0 10px 35px rgba(0, 229, 255, 0.1);
    }
    
    .nav-left {
      display: flex;
      align-items: center;
      gap: 8px;
    }
    
    .nav-icon-btn {
      width: 42px;
      height: 42px;
      border-radius: 14px;
      background: rgba(255,255,255,0.03);
      border: 1px solid rgba(255,255,255,0.08);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--text-body);
      font-size: 1.2rem;
      transition: var(--transition-smooth);
      cursor: pointer;
      backdrop-filter: blur(5px);
    }
    
    .nav-icon-btn:hover {
      border-color: var(--primary-cyan);
      color: var(--primary-cyan);
      box-shadow: 0 0 15px rgba(0,229,255,0.3);
      background: rgba(0,229,255,0.05);
    }
    
    .brand-logo {
      font-size: 1.6rem;
      font-weight: 700;
      letter-spacing: 0.5px;
      color: var(--primary-cyan);
      margin: 0 15px;
      text-shadow: 0 0 12px rgba(0,229,255,0.5);
    }
    
    .nav-right .btn-cta {
      background: linear-gradient(135deg, #00E5FF, #7B68EE);
      color: #0A0E27;
      padding: 12px 28px;
      border-radius: 30px;
      font-weight: 700;
      font-size: 0.95rem;
      letter-spacing: 0.5px;
      box-shadow: 0 4px 20px rgba(0,229,255,0.45);
      border: none;
      cursor: pointer;
      transition: var(--transition-smooth);
      white-space: nowrap;
    }
    
    .nav-right .btn-cta:hover {
      box-shadow: 0 8px 30px rgba(0,229,255,0.7);
      transform: scale(1.03);
    }
    
    /* 移动端导航适配 */
    @media (max-width: 768px) {
      .main-header {
        top: 10px;
        width: calc(100% - 20px);
        padding: 8px 15px;
      }
      .nav-icon-btn span {
        display: none;
      }
      .brand-logo {
        font-size: 1.3rem;
        margin: 0 5px;
      }
      .nav-right .btn-cta {
        padding: 10px 18px;
        font-size: 0.8rem;
      }
    }
    
    /* ----- Hero 首屏 ----- */
    .hero-section {
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding-top: 100px;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      background-repeat: no-repeat;
      position: relative;
    }
    
    .hero-section::before {
      content: '';
      position: absolute;
      inset: 0;
      background: radial-gradient(circle at 30% 40%, rgba(0,229,255,0.12) 0%, rgba(10,14,39,0.85) 70%);
      z-index: 1;
    }
    
    .hero-content {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      gap: 60px;
      flex-wrap: wrap;
    }
    
    .hero-left {
      flex: 1 1 500px;
    }
    
    .hero-left h1 {
      font-size: clamp(2.5rem, 5vw, 3.5rem);
      font-weight: 700;
      color: var(--text-white);
      line-height: 1.2;
      margin-bottom: 1.5rem;
      letter-spacing: -0.5px;
    }
    
    .hero-left .subtitle {
      font-size: 1.2rem;
      color: var(--text-body);
      margin-bottom: 2.2rem;
      max-width: 550px;
    }
    
    .hero-actions {
      display: flex;
      align-items: center;
      gap: 25px;
      flex-wrap: wrap;
    }
    
    .btn-glow {
      background: linear-gradient(135deg, #00E5FF, #7B68EE);
      color: #0A0E27;
      padding: 16px 36px;
      border-radius: 40px;
      font-weight: 700;
      font-size: 1.1rem;
      box-shadow: 0 8px 28px rgba(0,229,255,0.5);
      transition: var(--transition-smooth);
      display: inline-block;
      text-align: center;
    }
    
    .btn-glow:hover {
      box-shadow: 0 12px 35px rgba(0,229,255,0.75);
      transform: translateY(-2px);
    }
    
    .link-demo {
      color: var(--primary-cyan);
      font-weight: 500;
      border-bottom: 1px solid transparent;
    }
    .link-demo:hover {
      border-bottom-color: var(--primary-cyan);
      color: white;
    }
    
    .hero-right {
      flex: 1 1 300px;
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(15px);
      border: 1px solid rgba(0,229,255,0.2);
      border-radius: 24px;
      padding: 28px 25px;
      display: flex;
      flex-direction: column;
      gap: 22px;
    }
    
    .metric-mini {
      display: flex;
      justify-content: space-between;
      align-items: baseline;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      padding-bottom: 10px;
    }
    
    .metric-mini .value {
      font-size: 2rem;
      font-weight: 800;
      color: var(--primary-cyan);
      text-shadow: 0 0 15px #00E5FF;
    }
    
    @media (max-width: 768px) {
      .hero-content {
        flex-direction: column;
      }
      .hero-right {
        width: 100%;
      }
    }
    
    /* ----- 指标看板 ----- */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
      margin-top: 20px;
    }
    
    .metric-card {
      background: var(--card-bg);
      border: 1px solid var(--card-border);
      border-radius: var(--border-radius-lg);
      padding: 32px 20px;
      text-align: center;
      backdrop-filter: blur(10px);
      transition: var(--transition-smooth);
    }
    
    .metric-card:hover {
      border-color: var(--card-hover-border);
      box-shadow: var(--card-hover-shadow);
      transform: translateY(-5px);
    }
    
    .metric-number {
      font-size: 3rem;
      color: var(--primary-cyan);
      text-shadow: 0 0 18px rgba(0,229,255,0.7);
      margin-bottom: 8px;
    }
    
    @media (max-width: 992px) {
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 520px) {
      .metrics-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* ----- 服务矩阵 2x3 ----- */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    
    .service-card {
      background: var(--card-bg);
      border: 1px solid var(--card-border);
      border-radius: var(--border-radius-lg);
      padding: 32px 26px;
      backdrop-filter: blur(10px);
      transition: var(--transition-smooth);
      display: flex;
      flex-direction: column;
    }
    
    .service-card:hover {
      border-color: var(--card-hover-border);
      box-shadow: var(--card-hover-shadow);
      transform: translateY(-6px);
      background: rgba(255,255,255,0.06);
    }
    
    .service-icon {
      font-size: 2.4rem;
      color: var(--primary-cyan);
      margin-bottom: 20px;
    }
    
    .service-card h3 {
      color: white;
      font-size: 1.5rem;
      margin-bottom: 12px;
    }
    
    .card-link {
      color: var(--primary-cyan);
      margin-top: 18px;
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    
    @media (max-width: 992px) {
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 600px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* ----- 对比区 ----- */
    .comparison-wrapper {
      display: flex;
      gap: 30px;
      align-items: center;
    }
    
    .vs-divider {
      font-size: 2rem;
      font-weight: bold;
      color: var(--primary-cyan);
      text-shadow: 0 0 20px cyan;
    }
    
    .compare-card {
      flex: 1;
      background: var(--card-bg);
      border-radius: var(--border-radius-lg);
      padding: 30px;
      backdrop-filter: blur(12px);
    }
    
    .compare-card.before {
      border: 1px solid rgba(255,82,82,0.25);
    }
    .compare-card.after {
      border: 1px solid rgba(0,229,255,0.4);
      background: rgba(0,229,255,0.02);
    }
    
    @media (max-width: 768px) {
      .comparison-wrapper {
        flex-direction: column;
      }
      .vs-divider {
        transform: rotate(90deg);
      }
    }
    
    /* ----- FAQ 手风琴 ----- */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--card-bg);
      border: 1px solid var(--card-border);
      border-radius: var(--border-radius-md);
      margin-bottom: 16px;
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
      color: white;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      padding: 0 24px;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    
    /* ----- 表单区 ----- */
    .contact-card {
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(20px);
      border: 1px solid rgba(0,229,255,0.2);
      border-radius: 24px;
      padding: 45px;
      max-width: 600px;
      margin: 0 auto;
    }
    .input-field {
      width: 100%;
      background: rgba(0,0,0,0.4);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: 8px;
      padding: 14px 18px;
      color: white;
      margin-bottom: 18px;
    }
    .input-field:focus {
      border-color: var(--primary-cyan);
      box-shadow: 0 0 15px rgba(0,229,255,0.3);
    }
    
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1.5fr;
      gap: 30px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* 装饰性标题下划线 */
    .section-title {
      font-size: 2.3rem;
      font-weight: 600;
      color: white;
      margin-bottom: 15px;
      position: relative;
      display: inline-block;
    }
    .section-title::after {
      content: '';
      position: absolute;
      bottom: -8px;
      left: 0;
      width: 60px;
      height: 2px;
      background: var(--primary-cyan);
      box-shadow: 0 0 12px var(--primary-cyan);
    }