/* roulang page: index */
:root {
      --deep-space: #0B0E14;
      --aurora-green: #00E5A0;
      --star-silver: #C0C8D4;
      --card-bg: #141A22;
      --white: #FFFFFF;
      --text-primary: #F0F2F5;
      --text-secondary: #8A93A0;
      --border-subtle: rgba(192, 200, 212, 0.15);
      --shadow-card: 0 8px 30px rgba(0, 0, 0, 0.6);
      --shadow-aurora: 0 4px 20px rgba(0, 229, 160, 0.12);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-pill: 50px;
      --transition: 300ms cubic-bezier(0.2, 0.0, 0, 1.0);
      --font-mono: 'Inter', 'SF Mono', 'Fira Code', monospace;
      --font-sans: 'Inter', 'Noto Sans SC', '思源黑体', system-ui, -apple-system, sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--deep-space);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
      width: 100%;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      padding: 16px 0;
      transition: background 0.3s, box-shadow 0.3s, border 0.3s;
      background: transparent;
    }

    .header.scrolled {
      background: rgba(11, 14, 20, 0.92);
      backdrop-filter: blur(16px);
      border-bottom: 1px solid var(--aurora-green);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    }

    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }

    .logo {
      display: flex;
      flex-direction: column;
      align-items: flex-start;
      text-decoration: none;
      color: inherit;
    }

    .logo-cn {
      font-size: 1.5rem;
      font-weight: 700;
      letter-spacing: 2px;
      color: var(--white);
      line-height: 1.2;
    }

    .logo-en {
      font-size: 0.8rem;
      font-weight: 400;
      color: var(--star-silver);
      letter-spacing: 2px;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-links a {
      color: var(--star-silver);
      text-decoration: none;
      font-weight: 500;
      font-size: 1rem;
      transition: color 0.2s;
      position: relative;
    }

    .nav-links a:hover {
      color: var(--aurora-green);
    }

    .nav-cta {
      background: var(--aurora-green);
      color: #0B0E14 !important;
      padding: 10px 24px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      transition: box-shadow 0.3s, transform 0.2s;
    }

    .nav-cta:hover {
      box-shadow: 0 0 20px rgba(0, 229, 160, 0.5);
      transform: translateY(-2px);
    }

    /* 移动端底部导航 */
    .mobile-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: rgba(11, 14, 20, 0.9);
      backdrop-filter: blur(20px);
      border-top: 1px solid rgba(0, 229, 160, 0.3);
      padding: 12px 16px;
      z-index: 1001;
      justify-content: space-around;
    }

    .mobile-nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: var(--star-silver);
      font-size: 0.7rem;
      gap: 4px;
      text-decoration: none;
    }

    .mobile-nav-item.active {
      color: var(--aurora-green);
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      background: radial-gradient(circle at 30% 40%, #0f1825 0%, #0B0E14 80%);
      overflow: hidden;
    }

    #starCanvas {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      pointer-events: none;
      z-index: 1;
    }

    .hero-content {
      position: relative;
      z-index: 2;
      text-align: center;
      max-width: 900px;
      padding: 0 24px;
    }

    .hero h1 {
      font-size: 56px;
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.2;
      margin-bottom: 24px;
      color: var(--white);
    }

    .hero-sub {
      font-size: 1.6rem;
      color: var(--star-silver);
      margin-bottom: 48px;
      font-weight: 400;
    }

    .hero-buttons {
      display: flex;
      gap: 24px;
      justify-content: center;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--aurora-green);
      color: #0B0E14;
      padding: 16px 40px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      text-decoration: none;
      transition: box-shadow 0.3s, transform 0.2s;
      display: inline-block;
    }

    .btn-primary:hover {
      box-shadow: 0 0 30px rgba(0, 229, 160, 0.8);
      transform: translateY(-3px);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--star-silver);
      color: var(--star-silver);
      padding: 16px 40px;
      border-radius: var(--radius-pill);
      font-weight: 500;
      text-decoration: none;
      transition: 0.3s;
    }

    .btn-outline:hover {
      background: rgba(0, 229, 160, 0.1);
      border-color: var(--aurora-green);
      color: var(--aurora-green);
    }

    /* 通用区块 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 40px;
      font-weight: 700;
      letter-spacing: -0.01em;
      margin-bottom: 16px;
      color: var(--white);
    }

    .section-desc {
      color: var(--star-silver);
      font-size: 1.2rem;
      max-width: 700px;
    }

    /* 指标看板 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: 48px;
    }

    .metric-card {
      background: var(--card-bg);
      border-radius: var(--radius-sm);
      padding: 32px 24px;
      box-shadow: var(--shadow-aurora);
      border: 1px solid rgba(0, 229, 160, 0.2);
      transition: transform 0.3s;
    }

    .metric-card:hover {
      transform: translateY(-6px);
      box-shadow: 0 12px 28px rgba(0,229,160,0.2);
    }

    .metric-number {
      font-family: var(--font-mono);
      font-size: 48px;
      font-weight: 700;
      color: var(--aurora-green);
    }

    .metric-label {
      color: var(--star-silver);
      margin-top: 8px;
    }

    /* 服务矩阵不对称 */
    .service-grid {
      display: grid;
      grid-template-columns: 8fr 4fr;
      gap: 24px;
      margin-top: 48px;
    }

    .service-large {
      background: var(--card-bg);
      border-radius: var(--radius-md);
      padding: 0;
      overflow: hidden;
      box-shadow: var(--shadow-card);
      display: flex;
      flex-direction: column;
    }

    .service-large img {
      width: 100%;
      height: 220px;
      object-fit: cover;
      display: block;
    }

    .service-large-body {
      padding: 32px;
    }

    .tag-list {
      display: flex;
      gap: 12px;
      flex-wrap: wrap;
      margin: 16px 0;
    }

    .tag {
      background: rgba(0,229,160,0.1);
      color: var(--aurora-green);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 0.8rem;
    }

    .service-small {
      background: var(--card-bg);
      border-radius: var(--radius-md);
      padding: 28px;
      border: 1px solid transparent;
      transition: border 0.3s;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .service-small:hover {
      border-color: var(--aurora-green);
    }

    /* 对比区 */
    .compare-wrapper {
      display: flex;
      align-items: center;
      gap: 0;
      margin-top: 48px;
      background: #11161e;
      border-radius: 16px;
      overflow: hidden;
    }

    .compare-before, .compare-after {
      flex: 1;
      padding: 40px;
    }

    .compare-before {
      background: #1a1e26;
      color: #aaa;
    }

    .compare-after {
      background: #0f1a1f;
      color: white;
      border-left: 2px solid var(--aurora-green);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(192,200,212,0.2);
      padding: 24px 0;
    }

    .faq-question {
      font-weight: 600;
      font-size: 1.2rem;
      display: flex;
      align-items: center;
      gap: 12px;
      cursor: pointer;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--star-silver);
      padding-left: 32px;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }

    /* CTA */
    .cta-section {
      background: #0a0f16;
      text-align: center;
    }

    .input-group {
      display: flex;
      max-width: 500px;
      margin: 32px auto;
    }

    .input-group input {
      flex: 1;
      background: transparent;
      border: 1px solid var(--star-silver);
      padding: 16px;
      border-radius: 40px 0 0 40px;
      color: white;
    }

    .input-group button {
      background: var(--aurora-green);
      border: none;
      padding: 0 32px;
      border-radius: 0 40px 40px 0;
      font-weight: 600;
    }

    footer {
      padding: 60px 0;
      text-align: center;
      color: var(--star-silver);
    }

    @media (max-width: 1024px) {
      .service-grid { grid-template-columns: 1fr; }
      .metrics-grid { grid-template-columns: repeat(2,1fr); }
    }

    @media (max-width: 768px) {
      .header { display: none; }
      .mobile-nav { display: flex; }
      .hero h1 { font-size: 36px; }
      .metrics-grid { grid-template-columns: 1fr; }
      .compare-wrapper { flex-direction: column; }
    }