/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary-dark: #1A1F24;
      --primary-deep: #0B0E11;
      --accent: #00B894;
      --accent-glow: #00E6AE;
      --bg-light: #F8F9FA;
      --bg-green-light: #E8F5F0;
      --bg-red-light: #FDECEA;
      --text-heading: #0B0E11;
      --text-body: #2D3436;
      --text-muted: #636E72;
      --border-light: #E1E8ED;
      --white: #FFFFFF;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 24px rgba(0,0,0,0.08);
      --radius-md: 12px;
      --radius-btn: 8px;
      --transition-base: 0.25s ease-out;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --max-width: 1280px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--text-body);
      line-height: 1.6;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }

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

    /* 排版辅助 */
    h1, h2, h3 {
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-heading);
    }

    h2 {
      font-size: 2.5rem;
      margin-bottom: 1rem;
    }

    .section-padding {
      padding: 100px 0;
    }

    @media (max-width: 768px) {
      h2 {
        font-size: 2rem;
      }
      .section-padding {
        padding: 70px 0;
      }
    }

    /* ----- 导航栏 (透明转白底) ----- */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      padding: 16px 0;
    }

    .navbar.scrolled {
      background: var(--white);
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    }

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

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 1.7rem;
      font-weight: 700;
      color: var(--primary-dark);
      letter-spacing: -0.5px;
    }

    .logo-dot {
      width: 12px;
      height: 12px;
      background: var(--accent);
      border-radius: 50%;
      display: inline-block;
      box-shadow: 0 0 8px var(--accent-glow);
    }

    .nav-links {
      display: flex;
      gap: 2.5rem;
      align-items: center;
      font-weight: 500;
      color: var(--text-body);
    }

    .nav-links a {
      position: relative;
      padding-bottom: 6px;
      font-size: 1rem;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.25s ease, left 0.25s ease;
    }

    .nav-links a:hover {
      color: var(--accent);
    }

    .nav-links a:hover::after {
      width: 100%;
      left: 0;
    }

    .menu-toggle {
      display: none;
      font-size: 1.8rem;
      color: var(--primary-dark);
      background: none;
      border: none;
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: var(--white);
        flex-direction: column;
        justify-content: center;
        gap: 2.5rem;
        font-size: 2rem;
        transform: translateX(100%);
        transition: transform 0.35s ease;
        z-index: 999;
      }
      .nav-links.active {
        transform: translateX(0);
      }
      .menu-toggle {
        display: block;
        z-index: 1001;
      }
      .navbar.scrolled .menu-toggle {
        color: var(--primary-dark);
      }
    }

    /* ----- 按钮系统 ----- */
    .btn-primary {
      background: var(--accent);
      color: var(--white);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: background 0.2s, box-shadow 0.2s;
      border: none;
      box-shadow: 0 4px 12px rgba(0,184,148,0.2);
    }

    .btn-primary:hover {
      background: #00A881;
      box-shadow: 0 8px 18px rgba(0,184,148,0.35);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent);
      color: var(--accent);
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background 0.2s, color 0.2s;
    }

    .btn-outline:hover {
      background: rgba(0,184,148,0.08);
      color: #00A881;
    }

    /* ----- Hero 区域 ----- */
    .hero {
      padding: 160px 0 100px;
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
    }

    .hero-left {
      flex: 1;
    }

    .hero-left h1 {
      font-size: 3.5rem;
      font-weight: 800;
      margin-bottom: 1.5rem;
      color: var(--primary-deep);
      line-height: 1.15;
    }

    .hero-left p {
      font-size: 1.25rem;
      color: var(--text-muted);
      margin-bottom: 2.5rem;
      max-width: 90%;
    }

    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }

    .hero-right {
      flex: 1;
      position: relative;
      min-height: 380px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* 动态几何图形 (CSS 动效代替图片) */
    .geometry-animation {
      width: 100%;
      height: 100%;
      position: relative;
    }

    .circle, .line-flow {
      position: absolute;
      border-radius: 50%;
      background: radial-gradient(circle at 30% 30%, var(--accent), #1A1F24);
      opacity: 0.7;
    }

    .circle1 {
      width: 180px;
      height: 180px;
      top: 20px;
      left: 20px;
      animation: float 8s infinite alternate;
    }

    .circle2 {
      width: 120px;
      height: 120px;
      bottom: 30px;
      right: 30px;
      background: radial-gradient(circle, #2D3436, var(--accent));
      animation: float 6s infinite alternate-reverse;
    }

    .line-flow {
      width: 60px;
      height: 60px;
      background: transparent;
      border: 3px solid var(--accent);
      top: 50%;
      left: 50%;
      transform: translate(-50%,-50%);
      animation: rotate 12s linear infinite;
      border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
    }

    @keyframes float {
      0% { transform: translateY(0px); }
      100% { transform: translateY(-28px); }
    }
    @keyframes rotate {
      0% { transform: translate(-50%,-50%) rotate(0deg); }
      100% { transform: translate(-50%,-50%) rotate(360deg); }
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-left h1 {
        font-size: 2.5rem;
      }
      .hero-right {
        min-height: 280px;
      }
    }

    /* 数据看板 */
    .dashboard-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .stat-card {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 28px 24px;
      transition: all var(--transition-base);
    }
    .stat-card:hover {
      border-color: var(--accent);
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    .stat-icon {
      font-size: 2rem;
      color: var(--accent);
      margin-bottom: 16px;
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--primary-deep);
    }
    @media (max-width: 768px) {
      .dashboard-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    /* 服务矩阵 1+2 不对称 */
    .services-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .main-service {
      grid-row: span 2;
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 40px;
      position: relative;
      transition: all var(--transition-base);
    }
    .main-service::before {
      content: '';
      position: absolute;
      left: 0;
      top: 0;
      height: 100%;
      width: 6px;
      background: var(--accent);
      border-radius: 12px 0 0 12px;
    }
    .sub-service {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 32px;
      transition: all var(--transition-base);
    }
    .main-service:hover, .sub-service:hover {
      border-color: var(--accent);
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    @media (max-width: 768px) {
      .services-layout {
        grid-template-columns: 1fr;
      }
      .main-service {
        grid-row: span 1;
      }
    }

    /* 对比区 */
    .comparison-wrapper {
      display: flex;
      gap: 30px;
      align-items: stretch;
    }
    .compare-col {
      flex: 1;
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 32px;
    }
    .safe-col {
      background: var(--bg-green-light);
    }
    .risk-col {
      background: var(--bg-red-light);
    }
    .compare-item {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 14px 0;
      border-bottom: 1px dashed #ccc;
    }
    @media (max-width: 768px) {
      .comparison-wrapper {
        flex-direction: column;
      }
    }

    /* FAQ */
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 700;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    @media (max-width: 768px) {
      .faq-grid {
        grid-template-columns: 1fr;
      }
    }

    /* CTA 表单区 */
    .cta-dark {
      background: var(--primary-dark);
      color: white;
      border-radius: var(--radius-md);
      padding: 60px;
      display: flex;
      gap: 3rem;
    }
    .cta-left h3 {
      color: white;
      font-size: 2rem;
    }
    .input-underline {
      background: transparent;
      border: none;
      border-bottom: 2px solid #636E72;
      padding: 12px 4px;
      width: 100%;
      color: white;
      margin-bottom: 24px;
      outline: none;
      transition: border 0.2s;
    }
    .input-underline:focus {
      border-bottom-color: var(--accent);
    }
    .btn-submit {
      width: 100%;
      background: var(--accent);
      border: none;
      padding: 14px;
      font-weight: bold;
      color: white;
      border-radius: var(--radius-btn);
      position: relative;
      overflow: hidden;
    }
    .btn-submit::after {
      content: '';
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
      transition: left 0.5s;
    }
    .btn-submit:hover::after {
      left: 100%;
    }
    @media (max-width: 768px) {
      .cta-dark {
        flex-direction: column;
        padding: 32px;
      }
    }

    /* 页脚 */
    .footer {
      background: var(--primary-dark);
      color: #B0B8C1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }