/* roulang page: index */
:root {
      --speed-black: #1A1A1A;
      --essence-green: #C8FF00;
      --deep-charcoal: #2D2D2D;
      --pure-white: #FFFFFF;
      --light-gray: #B0B0B0;
      --mid-gray: #E0E0E0;
      --burst-orange: #FF4D00;
      --bg-deep: #0D0D0D;
      --shadow-sm: 0 8px 20px rgba(0,0,0,0.6);
      --shadow-green: 0 20px 40px rgba(200,255,0,0.15);
      --border-light: 1px solid rgba(255,255,255,0.08);
      --radius-lg: 16px;
      --radius-sm: 8px;
      --radius-btn: 4px;
      --font-heavy: 'Inter', 'SF Pro Display', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --max-width: 1280px;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      background-color: var(--bg-deep);
      color: var(--light-gray);
      font-family: 'PingFang SC', 'Microsoft YaHei', 'SF Pro Display', 'Inter', sans-serif;
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    h1, h2, h3 {
      font-family: var(--font-heavy);
      font-weight: 700;
      letter-spacing: -0.02em;
    }

    a {
      text-decoration: none;
      color: inherit;
    }

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

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

    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      height: 80px;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: background 0.3s, backdrop-filter 0.3s;
      background: transparent;
    }
    .navbar.scrolled {
      background: rgba(13,13,13,0.85);
      backdrop-filter: blur(20px);
    }
    .nav-inner {
      width: min(100%, var(--max-width));
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 24px;
      height: 100%;
    }
    .logo {
      font-size: 1.7rem;
      font-weight: 800;
      color: var(--essence-green);
      text-shadow: 0 0 12px rgba(200,255,0,0.5);
      letter-spacing: 0.5px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .nav-links a {
      color: var(--pure-white);
      font-weight: 500;
      position: relative;
      padding: 6px 0;
      font-size: 0.95rem;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--burst-orange);
      transition: width 0.25s ease, left 0.25s ease;
    }
    .nav-links a:hover::after {
      width: 100%;
      left: 0;
    }
    .btn-primary-nav {
      background: var(--essence-green);
      color: var(--speed-black);
      font-weight: 700;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-size: 0.9rem;
      transition: all var(--transition-smooth);
      border: 2px solid var(--essence-green);
      box-shadow: 0 4px 0 rgba(0,0,0,0.2);
    }
    .btn-primary-nav:hover {
      background: var(--burst-orange);
      border-color: var(--burst-orange);
      color: black;
      box-shadow: 0 8px 24px rgba(255,77,0,0.5);
      transform: translateY(-1px);
    }
    .mobile-menu-icon {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 2rem;
      cursor: pointer;
      width: 32px;
    }
    .fullscreen-menu {
      display: none;
    }

    @media (max-width: 768px) {
      .navbar {
        top: auto;
        bottom: 16px;
        background: transparent;
        height: auto;
        justify-content: center;
      }
      .navbar.scrolled {
        background: transparent;
        backdrop-filter: none;
      }
      .nav-inner { display: none; }
      .mobile-bottom-nav {
        display: flex;
      }
    }

    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 16px;
      left: 16px;
      right: 16px;
      background: rgba(45,45,45,0.95);
      backdrop-filter: blur(24px);
      border-radius: 24px;
      padding: 8px 12px;
      z-index: 1001;
      justify-content: space-around;
      align-items: center;
      box-shadow: 0 8px 30px rgba(0,0,0,0.7);
    }
    .mobile-bottom-nav a {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: #aaa;
      font-size: 0.7rem;
      gap: 2px;
      padding: 8px 12px;
      border-radius: 16px;
      transition: all 0.2s;
    }
    .mobile-bottom-nav a i { font-size: 1.5rem; }
    .mobile-bottom-nav a.active {
      color: var(--essence-green);
    }
    /* Hero */
    .hero {
      height: 100vh;
      min-height: 700px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      background: radial-gradient(circle at 30% 40%, #1a1a1a 0%, #0D0D0D 90%);
      overflow: hidden;
    }
    .hero-canvas {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
    }
    .hero-content {
      text-align: center;
      z-index: 10;
      max-width: 900px;
      padding: 0 24px;
    }
    h1 {
      font-size: 4rem;
      color: #FFFFFF;
      text-shadow: 0 0 30px rgba(200,255,0,0.4);
      margin-bottom: 1.5rem;
      font-weight: 900;
    }
    .hero-sub {
      font-size: 1.3rem;
      color: var(--light-gray);
      margin-bottom: 2.5rem;
    }
    .cta-group {
      display: flex;
      gap: 20px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--essence-green);
      color: #000;
      font-weight: 700;
      padding: 16px 36px;
      border-radius: var(--radius-btn);
      font-size: 1rem;
      border: none;
      transition: 0.3s;
      box-shadow: 0 4px 0 rgba(0,0,0,0.5);
    }
    .btn-primary:hover {
      background: var(--burst-orange);
      box-shadow: 0 0 30px rgba(255,77,0,0.7);
    }
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--essence-green);
      color: var(--essence-green);
      padding: 16px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .scroll-arrow {
      position: absolute;
      bottom: 30px;
      font-size: 2rem;
      color: var(--essence-green);
      animation: bounce 2s infinite;
    }
    @keyframes bounce {
      0%,100%{transform:translateY(0);}50%{transform:translateY(12px);}
    }

    @media (max-width: 768px) {
      h1 { font-size: 2.5rem; }
    }

    section {
      padding: 120px 0;
    }
    .section-title {
      font-size: 2.5rem;
      color: white;
      margin-bottom: 3rem;
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .green-line {
      width: 4px;
      height: 42px;
      background: var(--essence-green);
    }

    .grid-2col {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 5rem;
    }
    .grid-img img {
      border-radius: var(--radius-lg);
      border: 1px solid rgba(200,255,0,0.15);
      width: 100%;
      object-fit: cover;
    }
    .text-block h3 { color: white; font-size: 1.8rem; margin-bottom: 1rem;}
    .learn-more { color: var(--essence-green); font-weight: 600; display: inline-flex; align-items: center; gap: 6px;}
    .learn-more:hover { gap: 12px; }

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

    .dark-bg {
      background: #151515;
    }

    .stats-row {
      display: flex;
      justify-content: space-around;
      text-align: center;
    }
    .stat-number {
      font-size: 4rem;
      color: var(--essence-green);
      font-weight: 900;
    }

    .horizontal-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding: 20px 0;
      scrollbar-width: thin;
      scrollbar-color: var(--essence-green) #222;
    }
    .case-card {
      min-width: 340px;
      height: 460px;
      background-size: cover;
      background-position: center;
      border-radius: var(--radius-lg);
      display: flex;
      align-items: flex-end;
      transition: transform 0.3s;
    }
    .case-card:hover { transform: translateY(-8px); }

    .timeline {
      position: relative;
      max-width: 800px;
      margin: 0 auto;
    }
    .timeline-item {
      display: flex;
      margin-bottom: 40px;
    }
    .timeline-dot {
      width: 16px; height: 16px; background: var(--essence-green); border-radius: 50%; margin-right: 24px; box-shadow: 0 0 20px var(--essence-green);
    }

    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .faq-item {
      border-bottom: 1px solid #333;
      padding: 18px 0;
    }
    .faq-question {
      display: flex; justify-content: space-between; cursor: pointer; color: white; font-weight: 600;
    }
    .faq-answer {
      max-height: 0; overflow: hidden; transition: 0.4s; color: var(--light-gray);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
      padding: 60px 0;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
      .faq-grid { grid-template-columns: 1fr; }
    }