/* roulang page: index */
* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --bg-primary: #0A0E17;
      --bg-secondary: #111827;
      --bg-card: rgba(17, 24, 39, 0.7);
      --text-primary: #FFFFFF;
      --text-body: #CBD5E1;
      --text-muted: #94A3B8;
      --accent-neon: #00F0FF;
      --accent-purple: #A855F7;
      --cta-orange: #F97316;
      --border-light: rgba(255, 255, 255, 0.06);
      --border-hover: rgba(0, 240, 255, 0.3);
      --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.4);
      --shadow-glow: 0 0 15px currentColor;
      --radius-card: 16px;
      --radius-btn: 9999px;
      --radius-img: 12px;
      --font-family: 'Inter', 'Noto Sans SC', system-ui, sans-serif;
      --container-max: 1280px;
      --section-gap: 120px;
      --card-padding: 32px;
    }
    body {
      font-family: var(--font-family);
      background-color: var(--bg-primary);
      color: var(--text-body);
      line-height: 1.7;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3, h4 {
      font-family: var(--font-family);
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.02em;
    }
    h1 {
      font-size: clamp(2.8rem, 6vw, 4.5rem);
      font-weight: 800;
      line-height: 1.1;
    }
    h2 {
      font-size: 2.2rem;
      font-weight: 700;
      margin-bottom: 1.5rem;
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 60px;
      height: 4px;
      background: var(--accent-neon);
      border-radius: 4px;
      box-shadow: 0 0 10px var(--accent-neon);
    }
    .section-title {
      margin-bottom: 3rem;
    }
    a {
      color: var(--accent-neon);
      text-decoration: none;
      transition: all 0.25s ease;
    }
    a:hover {
      text-decoration: underline;
      text-shadow: 0 0 8px var(--accent-neon);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-family);
      font-weight: 600;
      letter-spacing: 0.05em;
      text-transform: uppercase;
      border: none;
      background: transparent;
      transition: all 0.25s ease;
    }
    /* 导航栏 */
    .header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: transparent;
      transition: background 0.3s ease, backdrop-filter 0.3s ease;
      padding: 16px 0;
    }
    .header.scrolled {
      background: rgba(10, 14, 23, 0.85);
      backdrop-filter: blur(16px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      background: linear-gradient(135deg, var(--accent-neon), #ffffff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      letter-spacing: -0.02em;
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      text-transform: none;
      letter-spacing: normal;
      font-size: 0.95rem;
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--accent-neon);
      text-shadow: none;
      text-decoration: none;
    }
    .btn-primary {
      background: var(--accent-neon);
      color: #0A0E17;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: 0 0 10px rgba(0,240,255,0.4);
      display: inline-block;
      text-align: center;
      border: none;
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 0 20px var(--accent-neon);
      text-decoration: none;
      color: #0A0E17;
    }
    .btn-outline {
      border: 2px solid var(--accent-neon);
      color: var(--accent-neon);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      background: transparent;
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.1);
      transform: translateY(-2px);
      box-shadow: 0 0 15px var(--accent-neon);
    }
    .btn-cta {
      background: var(--cta-orange);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      box-shadow: 0 0 12px rgba(249,115,22,0.5);
      display: inline-block;
      text-align: center;
    }
    .btn-cta:hover {
      transform: scale(1.02);
      box-shadow: 0 0 25px var(--cta-orange);
      text-decoration: none;
      color: white;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 25px;
      height: 3px;
      background: white;
      border-radius: 2px;
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(10,14,23,0.98);
      backdrop-filter: blur(20px);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 2rem;
      z-index: 40;
    }
    .mobile-menu a {
      font-size: 1.5rem;
      color: white;
      border-left: 4px solid transparent;
      padding-left: 12px;
    }
    .mobile-menu a:hover {
      border-left-color: var(--accent-neon);
    }
    /* 卡片 */
    .card {
      background: var(--bg-card);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: var(--card-padding);
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      border-color: var(--border-hover);
      box-shadow: 0 8px 30px rgba(0, 240, 255, 0.15);
    }
    .glass-card {
      background: rgba(17, 24, 39, 0.7);
      backdrop-filter: blur(12px);
      border: 1px solid rgba(255,255,255,0.08);
    }
    /* 网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    section {
      padding: var(--section-gap) 0;
    }
    .hero {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
      min-height: 90vh;
      padding-top: 80px;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 24px;
      height: 450px;
      box-shadow: 0 0 40px rgba(0,240,255,0.25), 0 0 40px rgba(168,85,247,0.2);
      border: 1px solid rgba(255,255,255,0.1);
    }
    .decor-line {
      width: 4px;
      height: 100%;
      background: var(--accent-neon);
      border-radius: 4px;
      position: absolute;
      left: 0;
      top: 0;
    }
    .testimonial-card {
      background: rgba(17,24,39,0.8);
      backdrop-filter: blur(8px);
      border: 1px solid rgba(168,85,247,0.25);
      border-radius: 16px;
      padding: 28px;
    }
    .faq-item {
      background: var(--bg-secondary);
      border-left: 4px solid var(--accent-neon);
      border-radius: 12px;
      margin-bottom: 16px;
      padding: 20px;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    input {
      background: #1E293B;
      border: 1px solid #334155;
      border-radius: 8px;
      padding: 12px 16px;
      color: white;
      width: 100%;
    }
    input:focus {
      outline: none;
      border-color: var(--accent-neon);
      box-shadow: 0 0 8px var(--accent-neon);
    }
    footer {
      background: #05080F;
      padding: 60px 0 30px;
    }
    @media (max-width: 1024px) {
      .grid-3, .grid-4 { grid-template-columns: repeat(2,1fr); }
      .hero { grid-template-columns: 1fr; text-align: center; }
      .hero-image { height: 300px; }
    }
    @media (max-width: 640px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .grid-3, .grid-2, .grid-4 { grid-template-columns: 1fr; }
      section { padding: 80px 0; }
      .container { padding: 0 16px; }
    }
    .fade-in {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-in.visible {
      opacity: 1;
      transform: translateY(0);
    }