/* roulang page: index */
:root {
      --bg-deep: #0A0E27;
      --accent-cyan: #00F0FF;
      --accent-red: #FF4655;
      --card-dark: #1A1F3A;
      --card-light: #F4F4F7;
      --text-primary: #FFFFFF;
      --text-secondary: #CBCFE0;
      --text-dim: #8B92AB;
      --border-glow: rgba(0,240,255,0.25);
      --shadow-cyan: 0 8px 32px rgba(0,240,255,0.08);
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --transition-smooth: all 0.3s ease;
      --container-max: 1280px;
      --section-gap: 100px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, -apple-system, sans-serif;
      background-color: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.6;
      font-weight: 400;
      font-size: 16px;
    }

    .rajdhani-font {
      font-family: 'Rajdhani', "PingFang SC", "Microsoft YaHei", sans-serif;
      font-weight: 700;
    }

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

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

    .container {
      max-width: var(--container-max);
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
      width: 100%;
    }

    .section {
      padding-top: var(--section-gap);
      padding-bottom: var(--section-gap);
    }

    @media (max-width: 1024px) {
      .section {
        padding-top: 80px;
        padding-bottom: 80px;
      }
    }

    @media (max-width: 768px) {
      .container {
        padding-left: 20px;
        padding-right: 20px;
      }
      .section {
        padding-top: 60px;
        padding-bottom: 60px;
      }
    }

    /* header / nav */
    header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background-color: rgba(10, 14, 39, 0.85);
      backdrop-filter: blur(16px);
      border-bottom: 1px solid rgba(0,240,255,0.15);
      transition: background 0.3s, border 0.3s;
    }
    header.scrolled {
      background-color: rgba(10, 14, 39, 0.965);
      border-bottom-color: var(--accent-cyan);
      box-shadow: 0 4px 14px rgba(0,240,255,0.06);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo-group {
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      color: var(--accent-cyan);
    }
    .logo-text {
      font-size: 26px;
      font-weight: 800;
      letter-spacing: -0.5px;
      color: white;
    }
    .logo-text span {
      color: var(--accent-cyan);
    }
    nav {
      display: flex;
      align-items: center;
      gap: 36px;
    }
    .nav-link {
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 16px;
      position: relative;
    }
    .nav-link:hover {
      color: var(--accent-cyan);
    }
    .btn-cta-nav {
      background: var(--accent-cyan);
      color: var(--bg-deep);
      font-weight: 700;
      padding: 10px 24px;
      border-radius: 40px;
      border: none;
      font-size: 15px;
      cursor: pointer;
      transition: var(--transition-smooth);
    }
    .btn-cta-nav:hover {
      background: #00D4E0;
      box-shadow: 0 0 18px rgba(0,240,255,0.5);
    }
    .burger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .burger span {
      width: 25px;
      height: 2.5px;
      background: var(--accent-cyan);
      border-radius: 4px;
      transition: 0.3s;
    }

    @media (max-width: 1024px) {
      .burger {
        display: flex;
      }
      nav {
        position: fixed;
        top: 0;
        right: 0;
        height: 100vh;
        width: 280px;
        background: #101428;
        flex-direction: column;
        align-items: flex-start;
        padding: 100px 30px 30px;
        gap: 30px;
        transform: translateX(100%);
        transition: 0.3s ease;
        backdrop-filter: blur(20px);
        border-left: 1px solid var(--border-glow);
        box-shadow: -8px 0 28px rgba(0,0,0,0.6);
      }
      nav.open {
        transform: translateX(0);
      }
    }

    /* hero */
    #hero {
      padding-top: 140px;
      padding-bottom: 80px;
      background: radial-gradient(circle at 30% 40%, rgba(0,240,255,0.08) 0%, transparent 60%);
      position: relative;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-title {
      font-size: 50px;
      font-weight: 800;
      line-height: 1.15;
      letter-spacing: -0.5px;
      background: linear-gradient(180deg, #00F0FF 15%, #ffffff 85%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-sub {
      color: #D0D5F0;
      font-size: 19px;
      margin: 24px 0 32px;
    }
    .badge-group {
      display: flex;
      gap: 28px;
      margin-bottom: 36px;
      flex-wrap: wrap;
    }
    .badge-item {
      background: rgba(0,240,255,0.08);
      border: 1px solid rgba(0,240,255,0.25);
      border-radius: 60px;
      padding: 10px 22px;
      font-weight: 600;
      color: var(--accent-cyan);
      font-size: 15px;
      backdrop-filter: blur(4px);
    }
    .btn-row {
      display: flex;
      gap: 18px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: var(--bg-deep);
      font-weight: 700;
      padding: 14px 32px;
      border-radius: 40px;
      border: none;
      cursor: pointer;
      transition: 0.3s;
      font-size: 15px;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #00D4E0;
      box-shadow: 0 0 22px rgba(0,240,255,0.55);
    }
    .btn-outline {
      border: 1.5px solid var(--accent-cyan);
      background: transparent;
      color: var(--accent-cyan);
      font-weight: 600;
      padding: 14px 30px;
      border-radius: 40px;
      transition: 0.3s;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
    }
    .hero-visual {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: 40px;
      height: 410px;
      mix-blend-mode: normal;
      box-shadow: 0 0 30px rgba(0,240,255,0.2);
      position: relative;
    }

    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
      }
      .hero-title {
        font-size: 39px;
      }
    }

    /* cards global */
    .cards-grid {
      display: grid;
      gap: 28px;
    }
    .cols-3 { grid-template-columns: repeat(3,1fr); }
    .cols-2 { grid-template-columns: repeat(2,1fr); }
    .cols-4 { grid-template-columns: repeat(4,1fr); }

    .card-base {
      background: var(--card-dark);
      border-radius: var(--radius-lg);
      padding: 32px;
      transition: var(--transition-smooth);
      border: 1px solid transparent;
    }
    .card-base:hover {
      transform: translateY(-6px);
      box-shadow: 0 20px 36px rgba(0,240,255,0.12);
      border-color: var(--accent-cyan);
    }

    .section-title {
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 16px;
    }

    #features .feature-icon { color: var(--accent-cyan); width: 48px; height: 48px; }
    #scenarios .scenario-card { background: var(--card-light); color: #1E2A3A; }
    #success .metric-badge { font-family: 'Rajdhani', sans-serif; }

    footer {
      background: #060918;
      padding: 60px 0 30px;
      border-top: 1px solid rgba(0,240,255,0.1);
    }

    @media (max-width: 768px) {
      .cols-3, .cols-4, .cols-2 { grid-template-columns: 1fr; }
    }