/* roulang page: index */
:root {
      --primary: #0A0E27;
      --accent-purple: #7C3AED;
      --accent-purple-light: #8B5CF6;
      --accent-cyan: #00F0FF;
      --bg-deep: #020617;
      --card-bg: rgba(17, 24, 39, 0.6);
      --text-main: #F1F5F9;
      --text-muted: #94A3B8;
      --border-glass: rgba(124, 58, 237, 0.2);
      --radius-card: 16px;
      --radius-btn: 12px;
      --shadow-glow: 0 8px 32px rgba(0, 0, 0, 0.4);
      --glow-purple: 0 0 18px rgba(124, 58, 237, 0.6);
      --glow-cyan: 0 0 20px rgba(0, 240, 255, 0.5);
      --container: 1280px;
      --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }

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

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

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

    @media (max-width: 640px) {
      .container {
        padding: 0 16px;
      }
    }

    h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
    }
    h2 {
      font-size: 36px;
      font-weight: 600;
      line-height: 1.3;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
      line-height: 1.4;
    }
    p, .text-body {
      font-size: 16px;
      line-height: 1.7;
      color: var(--text-muted);
    }
    a {
      color: var(--text-main);
      text-decoration: none;
      transition: color 0.2s;
    }
    a:hover {
      color: var(--accent-cyan);
    }

    /* Header / Navigation */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(2, 6, 23, 0.85);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(124, 58, 237, 0.4);
      transition: background 0.3s, box-shadow 0.3s;
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      margin: 0 auto;
      max-width: var(--container);
      padding: 0 24px;
    }
    .logo {
      display: flex;
      align-items: center;
      font-weight: 700;
      font-size: 24px;
      color: var(--text-main);
      letter-spacing: 1px;
    }
    .logo-icon {
      margin-right: 12px;
      color: var(--accent-cyan);
      font-size: 28px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-muted);
      transition: color 0.2s, text-shadow 0.2s;
    }
    .nav-links a:hover {
      color: var(--accent-cyan);
      text-shadow: 0 0 10px rgba(0, 240, 255, 0.6);
    }
    .hamburger {
      display: none;
      font-size: 28px;
      background: none;
      border: none;
      color: var(--text-main);
      cursor: pointer;
    }
    .mobile-menu {
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: rgba(2, 6, 23, 0.95);
      backdrop-filter: blur(24px);
      flex-direction: column;
      gap: 28px;
      padding: 40px 24px;
      display: none;
      border-bottom: 1px solid var(--border-glass);
    }
    .mobile-menu.open {
      display: flex;
    }
    .mobile-menu a {
      font-size: 20px;
      font-weight: 500;
      color: var(--text-main);
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .header-inner { padding: 0 16px; }
    }

    /* Hero */
    .hero-section {
      padding: 160px 0 100px;
      position: relative;
      overflow: hidden;
      background: radial-gradient(circle at 30% 50%, #1a1035 0%, #020617 75%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-content {
      flex: 1;
      z-index: 2;
    }
    .hero-content h1 {
      margin-bottom: 24px;
    }
    .gradient-text {
      background: linear-gradient(135deg, #00F0FF, #7C3AED);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-desc {
      font-size: 20px;
      color: var(--text-muted);
      margin-bottom: 40px;
      max-width: 580px;
    }
    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-purple);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      font-size: 16px;
      border: none;
      box-shadow: var(--glow-purple);
      cursor: pointer;
      transition: all 0.25s;
    }
    .btn-primary:hover {
      background: #8B5CF6;
      box-shadow: 0 0 28px rgba(0,240,255,0.7);
      transform: scale(1.02);
    }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--accent-purple);
      color: #A78BFA;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      cursor: pointer;
      transition: 0.2s;
    }
    .btn-secondary:hover {
      border-color: var(--accent-cyan);
      color: white;
      box-shadow: 0 0 15px rgba(0,240,255,0.4);
    }
    .hero-visual {
      flex: 1;
      position: relative;
    }
    .hero-img {
      width: 100%;
      border-radius: 20px;
      box-shadow: 0 20px 40px rgba(124,58,237,0.25);
    }
    .glow-blob {
      position: absolute;
      width: 350px;
      height: 350px;
      background: radial-gradient(circle, rgba(124,58,237,0.3) 0%, transparent 70%);
      border-radius: 50%;
      top: -50px;
      right: -80px;
      filter: blur(60px);
      z-index: 0;
    }
    @media (max-width: 768px) {
      .hero-grid { flex-direction: column; }
      .hero-section { padding: 140px 0 80px; }
      h1 { font-size: 36px; }
    }

    /* Glass Card */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(16px);
      border: 1px solid var(--border-glass);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-glow);
      padding: 28px;
      transition: 0.3s ease;
    }
    .glass-card:hover {
      border-color: rgba(124,58,237,0.5);
      box-shadow: 0 0 24px rgba(0,240,255,0.18);
      transform: translateY(-4px);
    }

    .section {
      padding: 100px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 16px;
    }
    .section-sub {
      text-align: center;
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto 60px;
    }

    /* Value Prop */
    .value-grid {
      display: flex;
      gap: 80px;
      align-items: center;
    }
    .value-metrics {
      display: flex;
      gap: 48px;
      flex-wrap: wrap;
    }
    .metric-num {
      font-size: 42px;
      font-weight: 700;
      color: var(--accent-cyan);
    }
    @media (max-width: 768px) {
      .value-grid { flex-direction: column; }
    }

    /* Features grid */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    @media (max-width: 1024px) { .features-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 640px) { .features-grid { grid-template-columns: 1fr; } }

    .feature-icon {
      font-size: 40px;
      color: var(--accent-cyan);
      margin-bottom: 20px;
      transition: 0.2s;
    }

    /* Scenarios */
    .scenario-row {
      display: flex;
      gap: 60px;
      align-items: center;
      margin-bottom: 80px;
    }
    .scenario-row.reverse {
      flex-direction: row-reverse;
    }
    .scenario-img {
      width: 50%;
      border-radius: 16px;
      box-shadow: 0 10px 30px rgba(0,0,0,0.4);
    }
    @media (max-width: 768px) {
      .scenario-row, .scenario-row.reverse { flex-direction: column; }
      .scenario-img { width: 100%; }
    }

    /* Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    @media (max-width: 768px) { .cases-grid { grid-template-columns: 1fr; } }

    /* Pricing */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
      align-items: start;
    }
    .pricing-highlight {
      border: 2px solid var(--accent-purple);
      box-shadow: 0 0 28px rgba(124,58,237,0.5);
    }
    .badge {
      background: var(--accent-cyan);
      color: #020617;
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
    }
    @media (max-width: 768px) { .pricing-grid { grid-template-columns: 1fr; } }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-left: 4px solid var(--accent-cyan);
      margin-bottom: 20px;
      background: var(--card-bg);
      border-radius: 12px;
      padding: 16px 24px;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      color: var(--text-main);
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.4s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    /* CTA */
    .cta-block {
      background: linear-gradient(135deg, #1a0f2e, #0A0E27);
      padding: 80px 0;
      text-align: center;
      position: relative;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      padding: 60px 0 30px;
    }
    .footer-bottom {
      border-top: 1px solid rgba(124,58,237,0.3);
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      color: var(--text-muted);
      font-size: 14px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }