/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --space-black: #0B0E1A;
      --star-gold: #F2B84B;
      --aurora-cyan: #5EEAD4;
      --gray-bg: #F5F7FA;
      --gray-mid: #6B7280;
      --gray-dark: #1F2937;
      --white: #FFFFFF;
      --card-bg-solid: #FFFFFF;
      --card-bg-ghost: rgba(255, 255, 255, 0.04);
      --card-border: rgba(255, 255, 255, 0.06);
      --shadow-medium: 0 8px 32px rgba(0, 0, 0, 0.12);
      --shadow-hover: 0 16px 48px rgba(0, 0, 0, 0.2);
      --radius-card: 16px;
      --radius-pill: 999px;
      --font-sans: "Inter", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, sans-serif;
      --container-max: 1280px;
      --space-section: 6rem;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      scroll-padding-top: 80px;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--space-black);
      color: var(--gray-mid);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: transparent;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all 0.2s ease;
      font-weight: 600;
      white-space: nowrap;
    }
    h1, h2, h3, h4 {
      color: var(--gray-dark);
      line-height: 1.2;
    }
    h1 {
      font-size: 3rem;
      font-weight: 700;
      letter-spacing: -0.5px;
      color: var(--white);
    }
    h2 {
      font-size: 2.25rem;
      font-weight: 700;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 600;
    }
    h4 {
      font-size: 1.125rem;
      font-weight: 500;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(11, 14, 26, 0.75);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      z-index: 1000;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--white);
      letter-spacing: 0.5px;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--star-gold);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 18px;
      color: var(--space-black);
    }
    .nav-links {
      display: flex;
      gap: 2.5rem;
      color: #D1D5DB;
      font-weight: 500;
    }
    .nav-links a:hover {
      color: var(--aurora-cyan);
    }
    .btn-pill {
      background: var(--star-gold);
      color: var(--space-black);
      padding: 10px 24px;
      border-radius: var(--radius-pill);
      font-weight: 600;
    }
    .btn-pill:hover {
      background: #F5C96A;
      box-shadow: 0 0 12px rgba(242, 184, 75, 0.5);
    }
    /* 移动端底部导航 */
    .mobile-nav {
      display: none;
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      background: radial-gradient(circle at 30% 40%, rgba(94, 234, 212, 0.06) 0%, transparent 50%), var(--space-black);
    }
    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 800 800"><circle cx="120" cy="100" r="2" fill="white" opacity="0.4"/><circle cx="600" cy="300" r="1.5" fill="white" opacity="0.3"/><circle cx="400" cy="150" r="2.5" fill="white" opacity="0.5"/><circle cx="700" cy="500" r="1" fill="white" opacity="0.25"/><circle cx="200" cy="650" r="2" fill="white" opacity="0.35"/><circle cx="550" cy="120" r="1.8" fill="white" opacity="0.4"/></svg>');
      background-size: cover;
      pointer-events: none;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
      width: 100%;
    }
    .hero-text {
      display: flex;
      flex-direction: column;
      gap: 1.5rem;
    }
    .hero-subtitle {
      font-size: 1.25rem;
      color: #D1D5DB;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--star-gold);
      color: var(--space-black);
      padding: 14px 32px;
      border-radius: var(--radius-pill);
      font-weight: 600;
    }
    .btn-primary:hover {
      background: #F5C96A;
      box-shadow: 0 0 16px rgba(242,184,75,0.6);
    }
    .btn-secondary {
      border: 1px solid var(--star-gold);
      color: var(--star-gold);
      padding: 14px 32px;
      border-radius: var(--radius-pill);
    }
    .btn-secondary:hover {
      background: rgba(242,184,75,0.08);
    }
    .hero-mockup {
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-mockup img {
      max-height: 500px;
      border-radius: 32px;
      box-shadow: 0 30px 60px rgba(0,0,0,0.5);
    }
    /* 区块通用 */
    section {
      padding: var(--space-section) 0;
    }
    .section-light {
      background: var(--gray-bg);
    }
    .section-dark {
      background: var(--space-black);
      color: #D1D5DB;
    }
    .section-dark h2, .section-dark h3 {
      color: var(--white);
    }
    .section-title {
      text-align: center;
      margin-bottom: 1rem;
    }
    .section-desc {
      text-align: center;
      max-width: 640px;
      margin: 0 auto 3rem;
      color: var(--gray-mid);
    }
    /* 服务卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .service-card {
      background: var(--card-bg-solid);
      border-radius: var(--radius-card);
      padding: 2rem;
      border: 1px solid rgba(0,0,0,0.04);
      box-shadow: var(--shadow-medium);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
      display: flex;
      flex-direction: column;
      gap: 1rem;
      position: relative;
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .service-card.featured {
      background: linear-gradient(145deg, #FFFFFF 0%, #F9FAFB 100%);
      border-top: 3px solid var(--aurora-cyan);
      box-shadow: 0 0 0 4px rgba(94,234,212,0.15);
    }
    .service-icon {
      width: 48px;
      height: 48px;
      color: var(--aurora-cyan);
      font-size: 2rem;
    }
    /* 数据优势 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 2rem;
      text-align: center;
    }
    .stat-number {
      font-size: 3.75rem;
      font-weight: 700;
      color: var(--star-gold);
      line-height: 1;
    }
    .stat-label {
      color: var(--gray-mid);
      margin-top: 0.5rem;
    }
    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 2rem;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-medium);
      transition: transform 0.3s ease;
    }
    .case-card:hover {
      transform: translateY(-4px);
    }
    .case-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
    }
    .case-body {
      padding: 1.5rem;
    }
    .case-tag {
      display: inline-block;
      background: rgba(94,234,212,0.15);
      color: #0F766E;
      font-size: 0.8rem;
      padding: 4px 10px;
      border-radius: 20px;
      margin-bottom: 0.5rem;
    }
    /* 解决方案交替 */
    .solution-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 4rem;
      align-items: center;
      margin-bottom: 5rem;
    }
    .solution-row.reverse {
      direction: rtl;
    }
    .solution-row.reverse .solution-text {
      direction: ltr;
    }
    .solution-img img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    }
    /* FAQ */
    .faq-list {
      max-width: 768px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid #E5E7EB;
      padding: 1.25rem 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 500;
      color: var(--gray-dark);
      cursor: pointer;
      width: 100%;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--gray-mid);
      line-height: 1.7;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: 0.75rem;
    }
    .faq-icon {
      font-size: 1.5rem;
      color: var(--aurora-cyan);
    }
    /* CTA */
    .cta-banner {
      background: linear-gradient(135deg, #0B0E1A 0%, #1a1f2e 100%);
      text-align: center;
      padding: 4rem 0;
      border-radius: 32px;
      margin: 0 24px;
      position: relative;
      overflow: hidden;
    }
    .cta-banner h2 {
      color: white;
    }
    .cta-btn {
      margin-top: 2rem;
    }
    /* 页脚 */
    .footer {
      background: #0B0E1A;
      color: #9CA3AF;
      padding: 4rem 0 2rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 3rem;
    }
    .footer h4 {
      color: white;
      margin-bottom: 1rem;
    }
    .footer a:hover {
      color: var(--star-gold);
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.07);
      margin-top: 3rem;
      padding-top: 2rem;
      text-align: center;
      font-size: 0.9rem;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 2.5rem; }
      h2 { font-size: 2rem; }
      .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-mockup { display: none; }
      .cards-grid { grid-template-columns: 1fr; }
      .stats-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: 1fr; }
      .solution-row { grid-template-columns: 1fr; gap:2rem; }
      .solution-row.reverse { direction: ltr; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .main-header .btn-pill { display: none; }
      .mobile-nav {
        display: flex;
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        background: rgba(11,14,26,0.92);
        backdrop-filter: blur(20px);
        justify-content: space-around;
        padding: 12px 16px;
        border-top: 1px solid rgba(255,255,255,0.08);
        z-index: 1000;
      }
      .mobile-nav a {
        color: #D1D5DB;
        display: flex;
        flex-direction: column;
        align-items: center;
        font-size: 0.75rem;
      }
      .footer-grid { grid-template-columns: 1fr; }
    }