/* roulang page: index */
:root {
      --deep-space: #0A0E17;
      --cold-gray: #F0F2F5;
      --emerald: #00E5A0;
      --coral: #FF6B4A;
      --amber: #FFD166;
      --text-dark: #3A4050;
      --text-light: #C0C6D0;
      --card-dark: #141B26;
      --card-white: #FFFFFF;
      --shadow-light: 0 4px 20px rgba(0,0,0,0.08);
      --shadow-emerald: 0 4px 20px rgba(0,229,160,0.08);
      --radius-lg: 12px;
      --radius-md: 8px;
      --font-mono: 'Inter', 'SF Mono', 'Roboto Mono', monospace;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --nav-width: 240px;
      --section-padding: 6rem;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--cold-gray);
      color: var(--text-dark);
      line-height: 1.8;
      margin: 0;
      display: flex;
      min-height: 100vh;
      scroll-behavior: smooth;
    }
    a {
      transition: color 0.2s ease, background-color 0.2s ease, transform 0.2s ease;
      text-decoration: none;
    }
    .left-nav {
      width: var(--nav-width);
      background-color: var(--deep-space);
      color: var(--text-light);
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      display: flex;
      flex-direction: column;
      z-index: 100;
      padding: 2rem 1.5rem;
      box-shadow: 2px 0 15px rgba(0,0,0,0.3);
    }
    .nav-logo {
      display: flex;
      align-items: center;
      gap: 0.75rem;
      margin-bottom: 2.5rem;
    }
    .logo-icon {
      width: 38px;
      height: 38px;
      background: conic-gradient(var(--emerald), var(--amber), var(--emerald));
      border-radius: 50%;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .logo-icon::after {
      content: "⚡";
      font-size: 1.4rem;
      color: var(--deep-space);
      font-weight: bold;
    }
    .logo-text {
      font-size: 1.5rem;
      font-weight: 700;
      background: linear-gradient(135deg, var(--emerald), #7effc7);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: 0.02em;
    }
    .nav-links {
      list-style: none;
      margin: 0;
      padding: 0;
      flex: 1;
    }
    .nav-links li {
      margin-bottom: 1.2rem;
    }
    .nav-links a {
      color: var(--text-light);
      font-weight: 500;
      display: block;
      padding: 0.4rem 0;
      border-left: 4px solid transparent;
      padding-left: 12px;
      transition: all 0.2s;
    }
    .nav-links a:hover, .nav-links a.active {
      color: white;
      border-left-color: var(--emerald);
      background: rgba(0,229,160,0.08);
    }
    .social-icons {
      display: flex;
      gap: 1.2rem;
      margin-top: 2rem;
      font-size: 1.3rem;
    }
    .social-icons a {
      color: var(--text-light);
    }
    .social-icons a:hover {
      color: var(--emerald);
      transform: translateY(-2px);
    }
    .main-content {
      margin-left: var(--nav-width);
      width: calc(100% - var(--nav-width));
      background: var(--cold-gray);
    }
    .mobile-header {
      display: none;
      background: var(--deep-space);
      color: white;
      padding: 1rem 2rem;
      align-items: center;
      justify-content: space-between;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 99;
      box-shadow: 0 2px 10px rgba(0,0,0,0.5);
    }
    .hamburger {
      font-size: 1.8rem;
      color: var(--emerald);
      cursor: pointer;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: rgba(10,14,23,0.95);
      backdrop-filter: blur(8px);
      z-index: 98;
      flex-direction: column;
      padding: 2rem;
      list-style: none;
    }
    .mobile-menu a {
      color: var(--text-light);
      padding: 0.8rem 0;
      font-size: 1.2rem;
      border-bottom: 1px solid rgba(255,255,255,0.1);
      display: block;
    }
    .container {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 2rem;
    }
    section {
      padding: var(--section-padding) 0;
    }
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      margin-bottom: 2.5rem;
      position: relative;
      padding-left: 1.5rem;
      color: var(--deep-space);
    }
    .section-title::before {
      content: '';
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      width: 4px;
      height: 40px;
      background: var(--emerald);
      border-radius: 2px;
    }
    .hero {
      background-color: var(--deep-space);
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
      padding: 8rem 0;
      color: white;
      text-align: center;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      top:0;left:0;right:0;bottom:0;
      background: rgba(10,14,23,0.75);
      backdrop-filter: blur(2px);
    }
    .hero-content {
      position: relative;
      z-index: 2;
    }
    .hero h1 {
      font-size: 3rem;
      font-weight: 800;
      color: white;
      margin-bottom: 1.5rem;
    }
    .hero h1 span {
      color: var(--emerald);
    }
    .hero p {
      font-size: 1.25rem;
      color: #B0B8C5;
      max-width: 700px;
      margin: 0 auto 2.5rem;
    }
    .btn-group {
      display: flex;
      gap: 1.5rem;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--emerald);
      color: var(--deep-space);
      font-weight: 700;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-md);
      border: none;
      transition: 0.2s;
    }
    .btn-primary:hover {
      background: #00f5b0;
      box-shadow: 0 0 15px rgba(0,229,160,0.6);
      color: #000;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--emerald);
      color: var(--emerald);
      font-weight: 700;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-md);
    }
    .btn-outline:hover {
      background: var(--emerald);
      color: var(--deep-space);
    }
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 2rem;
    }
    .metric-card {
      background: var(--card-dark);
      padding: 2rem 1.5rem;
      border-radius: var(--radius-lg);
      color: white;
      box-shadow: var(--shadow-emerald);
      transition: transform 0.2s;
    }
    .metric-card:hover {
      transform: translateY(-4px);
    }
    .metric-icon {
      font-size: 2rem;
      color: var(--emerald);
      margin-bottom: 1rem;
    }
    .metric-value {
      font-family: var(--font-mono);
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--emerald);
    }
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .service-card {
      background: var(--card-white);
      border-radius: var(--radius-lg);
      padding: 2rem 1.5rem;
      box-shadow: var(--shadow-light);
      transition: 0.2s;
      text-align: center;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: 0 10px 25px rgba(0,0,0,0.12);
    }
    .service-img {
      width: 100%;
      height: 160px;
      object-fit: cover;
      border-radius: var(--radius-md);
      margin-bottom: 1.5rem;
    }
    .compare-block {
      display: flex;
      gap: 3rem;
      background: white;
      border-radius: var(--radius-lg);
      padding: 3rem;
      align-items: center;
    }
    .chart-placeholder {
      background: #f0f2f5;
      height: 200px;
      border-radius: var(--radius-md);
      display: flex;
      align-items: flex-end;
      gap: 1.5rem;
      padding: 1rem;
    }
    .bar {
      width: 40px;
      background: #8A94A6;
      border-radius: 4px 4px 0 0;
      transition: height 0.3s;
    }
    .bar.green {
      background: linear-gradient(to top, var(--emerald), #7effc7);
    }
    .faq-item {
      background: white;
      border-radius: var(--radius-md);
      margin-bottom: 1rem;
      box-shadow: var(--shadow-light);
    }
    .faq-question {
      padding: 1.2rem 1.5rem;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      padding: 0 1.5rem 1.2rem;
      display: none;
      color: #555;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .cta-section {
      background: linear-gradient(135deg, #0A0E17 0%, #1a2535 100%);
      color: white;
      padding: 5rem 0;
      text-align: center;
    }
    .cta-form {
      max-width: 600px;
      margin: 2rem auto 0;
      display: flex;
      flex-direction: column;
      gap: 1rem;
    }
    .cta-form input, .cta-form select {
      padding: 0.9rem;
      border-radius: var(--radius-md);
      border: 1px solid #ccc;
      background: white;
    }
    .footer {
      background: var(--deep-space);
      color: #8A94A6;
      padding: 3rem 0;
    }
    @media (max-width: 1024px) {
      .left-nav { display: none; }
      .mobile-header { display: flex; }
      .main-content { margin-left: 0; width: 100%; }
      .metrics-grid { grid-template-columns: repeat(2, 1fr); }
      .services-grid { grid-template-columns: 1fr; }
      .compare-block { flex-direction: column; }
      .hero h1 { font-size: 2.2rem; }
    }

.mobile-menu.show { display: flex !important; flex-direction: column; }
    @media (min-width:1025px){ .mobile-menu { display: none !important; } }