/* roulang page: index */
:root {
      --primary-deep: #0A0E27;
      --accent-red: #E62E2E;
      --accent-red-dark: #C81E1E;
      --accent-cyan: #00F0FF;
      --card-bg: #1A1F3A;
      --card-bg-light: #1E2445;
      --text-soft: #6B7280;
      --bg-light: #F3F4F6;
      --white: #FFFFFF;
      --border-subtle: rgba(255,255,255,0.08);
      --shadow-card: 0 4px 24px rgba(0,0,0,0.4);
      --shadow-card-hover: 0 8px 32px rgba(0,240,255,0.15);
      --shadow-button: 0 2px 8px rgba(230,46,46,0.4);
      --shadow-button-hover: 0 4px 16px rgba(230,46,46,0.6);
      --radius-card: 12px;
      --radius-button: 8px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-mono: 'DIN Alternate', 'Roboto Mono', monospace;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--primary-deep);
      color: #E5E7EB;
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    a:hover {
      color: var(--accent-cyan);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
      outline: none;
    }
    /* 导航 */
    .main-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(10,14,39,0.88);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-subtle);
      z-index: 1000;
      transition: background 0.25s ease;
    }
    .main-nav.scrolled {
      background: rgba(10,14,39,0.98);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      padding: 0 24px;
      max-width: 1280px;
      margin: 0 auto;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--white);
      letter-spacing: 1px;
      text-transform: uppercase;
    }
    .logo i {
      color: var(--accent-cyan);
      font-size: 1.8rem;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      font-size: 0.95rem;
      color: #D1D5DB;
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--accent-cyan);
    }
    .btn-nav-cta {
      background: var(--accent-red);
      color: white !important;
      padding: 10px 20px;
      border-radius: var(--radius-button);
      font-weight: 600;
      margin-left: 8px;
      transition: background 0.2s, transform 0.2s;
    }
    .btn-nav-cta:hover {
      background: var(--accent-red-dark);
      transform: translateY(-1px);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 1.5rem;
      cursor: pointer;
    }
    @media (max-width: 1024px) {
      .nav-links {
        gap: 20px;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(10,14,39,0.97);
        backdrop-filter: blur(20px);
        flex-direction: column;
        justify-content: center;
        gap: 30px;
        transform: translateX(100%);
        transition: transform 0.35s ease;
        z-index: 999;
      }
      .nav-links.active {
        transform: translateX(0);
      }
      .nav-links a {
        font-size: 1.4rem;
      }
      .menu-toggle {
        display: block;
        z-index: 1001;
      }
      .btn-nav-cta {
        margin-left: 0;
      }
    }

    /* 板块通用 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }

    h2 {
      font-size: 2.25rem;
      font-weight: 700;
      margin-bottom: 48px;
      text-align: center;
      color: var(--white);
      letter-spacing: 0.5px;
    }
    @media (max-width: 768px) {
      h2 {
        font-size: 1.8rem;
        margin-bottom: 32px;
      }
    }

    /* 按钮 */
    .btn-primary {
      background: linear-gradient(135deg, var(--accent-red), var(--accent-red-dark));
      border: none;
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-button);
      font-weight: 600;
      cursor: pointer;
      box-shadow: var(--shadow-button);
      transition: all 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--accent-red-dark);
      transform: translateY(-2px);
      box-shadow: var(--shadow-button-hover);
      color: white;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 12px 28px;
      border-radius: var(--radius-button);
      font-weight: 600;
      transition: 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
      border-color: var(--accent-cyan);
      color: var(--accent-cyan);
      box-shadow: 0 0 8px rgba(0,240,255,0.3);
    }

    /* Hero */
    #hero {
      padding: 160px 0 100px;
      background: radial-gradient(circle at 30% 40%, #1c2340 0%, #0A0E27 70%);
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-left h1 {
      font-size: 3rem;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: 1px;
      color: white;
      margin-bottom: 24px;
    }
    .hero-left p {
      font-size: 1.1rem;
      color: var(--text-soft);
      max-width: 480px;
      margin-bottom: 36px;
    }
    .hero-actions {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-right {
      display: flex;
      flex-direction: column;
      gap: 20px;
      position: relative;
    }
    .stat-card {
      background: rgba(26,31,58,0.7);
      backdrop-filter: blur(5px);
      border: 1px solid rgba(0,240,255,0.18);
      border-radius: var(--radius-card);
      padding: 22px 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: fit-content;
      min-width: 220px;
      box-shadow: var(--shadow-card);
    }
    .stat-card .number {
      font-family: var(--font-mono);
      font-size: 2.4rem;
      font-weight: 900;
      color: var(--accent-cyan);
    }
    .stat-card .label {
      color: #ccc;
      font-size: 0.9rem;
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 48px;
      }
      .hero-left h1 {
        font-size: 2.2rem;
      }
    }

    /* metrics */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .metric-item {
      background: rgba(26,31,58,0.7);
      border: 1px solid rgba(0,240,255,0.18);
      border-radius: var(--radius-card);
      padding: 28px 20px;
      text-align: center;
      transition: 0.25s;
    }
    .metric-item:hover {
      border-color: rgba(0,240,255,0.5);
      box-shadow: var(--shadow-card-hover);
    }
    .metric-icon {
      font-size: 2rem;
      color: var(--accent-cyan);
      margin-bottom: 10px;
    }
    .metric-number {
      font-family: var(--font-mono);
      font-size: 3rem;
      font-weight: 900;
      color: var(--accent-cyan);
    }
    .trend-up {
      color: #f87171;
      font-size: 0.9rem;
      margin-left: 4px;
    }
    @media (max-width: 1024px) {
      .metrics-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 520px) {
      .metrics-grid {
        grid-template-columns: 1fr;
      }
    }

    /* services */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 28px;
    }
    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px;
      border-left: 5px solid var(--accent-red);
      transition: all 0.25s;
      display: flex;
      flex-direction: column;
    }
    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-card-hover);
      border-left-color: var(--accent-cyan);
    }
    .service-icon {
      font-size: 2.4rem;
      color: var(--accent-cyan);
      margin-bottom: 18px;
    }
    .service-card h3 {
      font-size: 1.4rem;
      font-weight: 600;
      margin-bottom: 12px;
      color: white;
    }
    .service-card p {
      color: #9CA3AF;
      margin-bottom: 24px;
      flex:1;
    }
    @media (max-width: 1024px) {
      .services-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 640px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* comparison */
    .comparison-wrapper {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
      
    }
    .compare-col {
      background: var(--card-bg);
      padding: 32px;
      border-radius: var(--radius-card);
    }
    .compare-col.highlight {
      background: var(--card-bg-light);
      border: 1px solid rgba(0,240,255,0.2);
    }
    .compare-row {
      display: flex;
      justify-content: space-between;
      padding: 14px 0;
      border-bottom: 1px solid rgba(255,255,255,0.08);
      align-items: center;
    }
    .compare-value {
      font-weight: 700;
    }
    .cyan-value {
      color: var(--accent-cyan);
    }
    @media (max-width: 768px) {
      .comparison-wrapper {
        grid-template-columns: 1fr;
      }
    }

    /* FAQ */
    #faq {
      background-color: var(--bg-light);
      color: #1F2937;
    }
    #faq h2 {
      color: #111827;
    }
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid #D1D5DB;
      padding: 16px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      padding: 8px 0;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: #4B5563;
    }
    .faq-answer.open {
      max-height: 200px;
      padding-top: 8px;
    }

    /* CTA */
    #cta {
      background: var(--bg-light);
      color: #1F2937;
    }
    .cta-card {
      background: white;
      border-radius: 16px;
      padding: 48px;
      max-width: 700px;
      margin: 0 auto;
      box-shadow: 0 12px 30px rgba(0,0,0,0.1);
      display: flex;
      gap: 24px;
      flex-wrap: wrap;
    }
    .cta-form {
      flex: 1;
    }
    .cta-form input, .cta-form textarea {
      width: 100%;
      border: 1px solid #D1D5DB;
      border-radius: 8px;
      padding: 12px;
      margin-bottom: 16px;
    }
    .cta-form input:focus, .cta-form textarea:focus {
      border-color: var(--accent-cyan);
    }
    .footer {
      background: #0A0E27;
      padding: 48px 0 24px;
      color: #9CA3AF;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      margin-bottom: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }