/* roulang page: index */
:root {
      --deep-blue: #0A0E27;
      --cyan: #00F0FF;
      --violet: #7B2FFF;
      --card-bg: rgba(255,255,255,0.04);
      --card-hover-bg: rgba(255,255,255,0.08);
      --border-light: rgba(255,255,255,0.08);
      --border-hover: rgba(255,255,255,0.15);
      --text-primary: #FFFFFF;
      --text-body: #B0B8D0;
      --text-muted: #6B7394;
      --glass-blur: blur(20px);
      --radius-card: 16px;
      --radius-btn: 12px;
      --radius-input: 8px;
      --shadow-glow-cyan: 0 0 24px rgba(0,240,255,0.4);
      --shadow-glow-violet: 0 0 24px rgba(123,47,255,0.4);
      --transition-smooth: all 0.3s ease;
      --container-max: 1200px;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
      background-color: var(--deep-blue);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    h1, h2, h3 {
      color: var(--text-primary);
      letter-spacing: -0.02em;
    }
    h1 {
      font-size: 56px;
      line-height: 1.1;
      font-weight: 800;
    }
    h2 {
      font-size: 40px;
      line-height: 1.2;
      font-weight: 700;
      margin-bottom: 2rem;
    }
    h3 {
      font-size: 24px;
      line-height: 1.3;
      font-weight: 600;
    }
    p {
      color: var(--text-body);
    }
    a {
      color: var(--cyan);
      text-decoration: none;
      transition: var(--transition-smooth);
    }
    a:hover {
      color: #fff;
    }
    .section-padding {
      padding: 100px 0;
    }
    @media (max-width: 1023px) {
      .section-padding { padding: 80px 0; }
      h1 { font-size: 44px; }
      h2 { font-size: 34px; }
    }
    @media (max-width: 767px) {
      .section-padding { padding: 60px 0; }
      h1 { font-size: 36px; }
      h2 { font-size: 28px; }
      h3 { font-size: 20px; }
    }

    /* glass card */
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      box-shadow: 0 8px 32px rgba(0,0,0,0.4);
      transition: var(--transition-smooth);
    }
    .glass-card:hover {
      background: var(--card-hover-bg);
      border-color: var(--border-hover);
      transform: translateY(-4px);
    }

    /* buttons */
    .btn-primary {
      background: linear-gradient(135deg, #00F0FF, #00C8FF);
      color: #0A0E27;
      font-weight: 700;
      border-radius: var(--radius-btn);
      padding: 16px 32px;
      border: none;
      box-shadow: var(--shadow-glow-cyan);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      box-shadow: 0 0 40px rgba(0,240,255,0.6);
      transform: scale(1.03);
      color: #0A0E27;
      background: linear-gradient(135deg, #33F5FF, #33D4FF);
    }
    .btn-secondary {
      background: transparent;
      border: 1px solid var(--cyan);
      color: var(--cyan);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 28px;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-secondary:hover {
      background: rgba(0,240,255,0.1);
      color: #fff;
      border-color: #fff;
    }
    .btn-violet {
      background: linear-gradient(135deg, #7B2FFF, #5A1FCC);
      color: white;
      font-weight: 700;
      border-radius: var(--radius-btn);
      padding: 16px 32px;
      border: none;
      box-shadow: var(--shadow-glow-violet);
      transition: var(--transition-smooth);
    }
    .btn-violet:hover {
      box-shadow: 0 0 40px rgba(123,47,255,0.6);
      transform: scale(1.03);
    }

    /* navbar */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      background: rgba(10,14,39,0.85);
      backdrop-filter: blur(24px);
      -webkit-backdrop-filter: blur(24px);
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }
    .navbar-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 1.5rem;
      height: 72px;
    }
    .logo {
      font-size: 22px;
      font-weight: 800;
      background: linear-gradient(135deg, #00F0FF, #7B2FFF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      gap: 2rem;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      position: relative;
      padding: 0.25rem 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--cyan);
      transition: 0.3s ease;
      transform: translateX(-50%);
    }
    .nav-links a:hover {
      color: var(--cyan);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .search-command {
      background: rgba(255,255,255,0.05);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: 8px;
      padding: 8px 16px;
      display: flex;
      align-items: center;
      gap: 8px;
      color: var(--text-muted);
      font-size: 14px;
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      color: #fff;
      background: none;
      border: none;
    }
    @media (max-width: 1023px) {
      .nav-links, .search-command { display: none; }
      .hamburger { display: block; }
    }

    /* hero */
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
      padding-top: 120px;
    }
    .hero-metrics {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .mini-stat {
      background: var(--card-bg);
      backdrop-filter: blur(16px);
      border: 1px solid var(--border-light);
      border-radius: 12px;
      padding: 16px 20px;
      flex: 1;
    }
    .metric-value {
      font-size: 28px;
      font-weight: 700;
      color: var(--cyan);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .pulse-dot {
      width: 8px;
      height: 8px;
      background: var(--cyan);
      border-radius: 50%;
      box-shadow: 0 0 12px var(--cyan);
      animation: pulse 1.5s infinite;
    }
    @keyframes pulse { 0%{opacity:0.5;} 50%{opacity:1;} 100%{opacity:0.5;} }
    @media (max-width: 767px) {
      .hero-grid { grid-template-columns: 1fr; }
    }

    /* data cards */
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .data-card {
      padding: 28px 24px;
    }
    .trend-bar {
      height: 24px;
      background: rgba(0,240,255,0.08);
      border-radius: 8px;
      margin-top: 12px;
      display: flex;
      align-items: flex-end;
      gap: 3px;
    }
    .trend-bar span {
      width: 6px;
      background: var(--cyan);
      border-radius: 4px;
      height: 70%;
    }
    @media (max-width: 1023px) { .data-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 767px) { .data-grid { grid-template-columns: 1fr; } }

    /* service grid */
    .service-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .service-card {
      padding: 32px;
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      margin-bottom: 1.5rem;
    }
    .bg-cyan-grad { background: linear-gradient(135deg, #00F0FF, #00A3CC); }
    .bg-violet-grad { background: linear-gradient(135deg, #7B2FFF, #4A1FAA); }
    @media (max-width: 1023px) { .service-grid { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 767px) { .service-grid { grid-template-columns: 1fr; } }

    /* comparison */
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 0;
      position: relative;
    }
    .divider-glow {
      width: 2px;
      background: rgba(0,240,255,0.3);
      box-shadow: 0 0 16px var(--cyan);
      margin: 0 24px;
    }
    .compare-card {
      padding: 32px;
    }
    @media (max-width: 767px) {
      .compare-grid { grid-template-columns: 1fr; }
      .divider-glow { display: none; }
    }

    /* steps */
    .steps-row {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
    }
    .step-item {
      text-align: center;
      flex: 1;
      position: relative;
    }
    .step-circle {
      width: 40px;
      height: 40px;
      border: 2px solid var(--cyan);
      border-radius: 50%;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      background: rgba(0,240,255,0.05);
      margin-bottom: 1rem;
    }
    .step-line {
      position: absolute;
      top: 20px;
      left: 70%;
      width: 60%;
      height: 1px;
      background: rgba(255,255,255,0.1);
    }
    @media (max-width: 767px) {
      .steps-row { flex-direction: column; gap: 2rem; }
      .step-line { display: none; }
    }

    /* faq */
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }
    .faq-question {
      cursor: pointer;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: rgba(255,255,255,0.02);
      border-radius: 8px;
      padding: 0 16px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px;
    }

    /* footer */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 2rem;
    }
    @media (max-width: 1023px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
    @media (max-width: 767px) { .footer-grid { grid-template-columns: 1fr; } }