/* roulang page: index */
:root {
      --primary-deep: #0B0E14;
      --primary-ice: #F4F7FA;
      --accent-aurora: #00E5A0;
      --accent-heat: #FF5E3A;
      --text-body: #3A3F47;
      --text-muted: #6C727A;
      --border-light: #E0E4E9;
      --card-bg: #FFFFFF;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 40px rgba(0,0,0,0.08);
      --radius-sm: 12px;
      --radius-pill: 100px;
      --transition: 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
      --font-stack: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Inter", -apple-system, sans-serif;
      --grid-gap: 1280px;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; font-size: 16px; }
    body {
      font-family: var(--font-stack);
      background: var(--primary-ice);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    img { max-width: 100%; display: block; }
    a { text-decoration: none; color: inherit; }

    .container {
      width: 100%;
      max-width: var(--grid-gap);
      margin: 0 auto;
      padding: 0 32px;
    }
    @media (max-width: 768px) {
      .container { padding: 0 20px; }
    }

    /* 主导航 */
    .main-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid transparent;
      transition: box-shadow var(--transition), border-color var(--transition);
      padding: 0;
    }
    .header-shadow {
      box-shadow: 0 2px 16px rgba(0,0,0,0.04);
      border-bottom: 1px solid var(--border-light);
    }
    .nav-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 1.5rem;
      letter-spacing: 0.08em;
      color: var(--primary-deep);
    }
    .logo-icon {
      width: 28px;
      height: 28px;
      background: var(--accent-aurora);
      mask: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><circle cx="12" cy="12" r="8" fill="none"/><path d="M6 16 Q12 4 18 16" stroke="black" fill="none"/></svg>') center/contain no-repeat;
      background: var(--accent-aurora);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      font-size: 0.95rem;
      color: var(--primary-deep);
      transition: color 0.2s;
      position: relative;
    }
    .nav-links a:hover { color: var(--accent-aurora); }
    .btn-nav {
      background: var(--accent-aurora);
      color: var(--primary-deep);
      font-weight: 700;
      padding: 0.6rem 1.8rem;
      border-radius: var(--radius-pill);
      font-size: 0.9rem;
      letter-spacing: 0.02em;
      transition: all var(--transition);
      box-shadow: 0 4px 10px rgba(0,229,160,0.3);
    }
    .btn-nav:hover {
      background: var(--primary-deep);
      color: white;
      box-shadow: 0 8px 20px rgba(0,229,160,0.5);
    }
    .burger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      width: 28px;
      background: none;
      border: none;
      padding: 4px;
    }
    .burger span {
      display: block;
      height: 2px;
      width: 100%;
      background: var(--primary-deep);
      border-radius: 10px;
      transition: var(--transition);
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      right: -100%;
      width: 80%;
      max-width: 320px;
      height: 100vh;
      background: rgba(11,14,20,0.96);
      backdrop-filter: blur(16px);
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 40px;
      transition: right var(--transition);
      z-index: 100;
    }
    .mobile-menu.open { right: 0; }
    .mobile-menu a {
      color: white;
      font-size: 1.4rem;
      font-weight: 600;
    }
    .mobile-menu .btn-nav { background: var(--accent-aurora); color: #0B0E14; padding: 12px 32px; }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .burger { display: flex; }
    }

    h2.section-title {
      font-weight: 700;
      letter-spacing: -0.02em;
      font-size: 2.2rem;
      color: var(--primary-deep);
      margin-bottom: 24px;
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .section-title::before {
      content: "";
      display: block;
      width: 40px;
      height: 4px;
      background: var(--accent-aurora);
      border-radius: 4px;
    }
    @media(min-width:1024px){
      .section-title { font-size: 3rem; }
    }

    section { padding: 80px 0; }
    @media(max-width:768px){ section{padding:60px 0;} }

    .hero {
      display: grid;
      grid-template-columns: 5fr 4fr;
      gap: 40px;
      align-items: center;
    }
    .hero-left h1 {
      font-weight: 800;
      letter-spacing: -0.03em;
      line-height: 1.1;
      font-size: 2.8rem;
      color: var(--primary-deep);
    }
    .hero-sub {
      font-size: 1.12rem;
      margin: 24px 0 32px;
    }
    .hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
    .btn-outline {
      border: 2px solid var(--primary-deep);
      padding: 0.8rem 2.2rem;
      border-radius: var(--radius-pill);
      font-weight: 700;
      background: transparent;
      transition: all var(--transition);
    }
    .btn-fill {
      background: var(--accent-aurora);
      color: var(--primary-deep);
      padding: 0.8rem 2.6rem;
      border-radius: var(--radius-pill);
      font-weight: 700;
      border: none;
      transition: all var(--transition);
      box-shadow: 0 8px 24px rgba(0,229,160,0.35);
    }
    .btn-fill:hover { background: white;  box-shadow: 0 12px 30px rgba(0,0,0,0.15); }
    .hero-right {
      position: relative;
      height: 400px;
      display: flex;
      align-items: center;
    }
    @media(max-width:768px){
      .hero{grid-template-columns:1fr;}
      .hero-right{height:260px; margin-top:20px; display: none;}
      .hero-left h1{ font-size: 2.5rem; }
    }

    .grid-features {
      display: grid;
      grid-template-columns: 1fr 1.2fr 0.8fr;
      gap: 28px;
      margin-top: 48px;
    }
    .feat-card {
      background: white;
      padding: 32px;
      border-radius: var(--radius-sm);
      box-shadow: var(--shadow-sm);
      transition: transform var(--transition), box-shadow var(--transition);
    }
    .feat-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); }
    .feat-card.dark {
      background: var(--primary-deep);
      color: var(--primary-ice);
    }
    .feat-icon {
      width: 48px; height: 48px;
      background: var(--accent-aurora);
      mask-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M13 2L3 14h6l-1 8 10-12h-6l1-8z"/></svg>');
      mask-size: contain;
      margin-bottom: 24px;
    }
    .feat-card h3{ font-weight:600; margin-bottom:12px; font-size:1.4rem; }
    @media(max-width: 900px){
      .grid-features{ grid-template-columns:1fr; }
    }

    .scenarios-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .scene-card {
      height: 380px;
      background-size: cover;
      background-position: center;
      border-radius: 16px;
      position: relative;
      overflow: hidden;
      display: flex;
      align-items: flex-end;
      color: white;
      transition: transform 0.3s;
    }
    .scene-card:hover { transform: scale(1.02); }
    .scene-overlay {
      background: linear-gradient(0deg, rgba(11,14,20,0.85) 0%, transparent 70%);
      padding: 40px;
      width: 100%;
    }
    .scene-white {
      background: white;
      color: var(--text-body);
      display: flex;
      flex-direction: column;
      justify-content: flex-start;
      padding: 40px;
    }
    @media(max-width:768px){
      .scenarios-grid{grid-template-columns:1fr;}
      .scene-card{height:240px;}
    }

    .numbers {
      display: flex;
      gap: 60px;
      justify-content: flex-start;
      flex-wrap: wrap;
      margin: 40px 0;
    }
    .num-item h3 {
      font-size: 3.5rem;
      font-weight: 800;
      color: var(--accent-aurora);
    }
    .cases-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 24px;
    }
    .case-card {
      background: white;
      border-radius: 16px;
      padding: 32px;
      box-shadow: var(--shadow-sm);
    }
    @media(max-width:768px){
      .cases-grid{grid-template-columns:1fr;}
    }

    .pricing-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .price-card {
      background: white;
      padding: 48px 32px;
      border-radius: 24px;
      box-shadow: var(--shadow-sm);
    }
    .price-card.featured {
      background: var(--primary-deep);
      color: white;
      border: 2px solid var(--accent-aurora);
      box-shadow: 0 0 24px rgba(0,229,160,0.2);
    }
    .badge {
      background: var(--accent-heat);
      color: white;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 0.75rem;
      font-weight: 700;
    }
    @media(max-width:768px){ .pricing-grid{grid-template-columns:1fr;} }

    .faq-list { max-width: 800px; margin: 0 auto; }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 24px 0;
      cursor: pointer;
    }
    .faq-question { display: flex; justify-content: space-between; align-items: center; font-weight: 600; }
    .faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s; }
    .faq-item.open .faq-answer { max-height: 200px; margin-top:16px; }

    .cta-block {
      background: var(--primary-deep);
      color: white;
      text-align: center;
      padding: 100px 20px;
      border-radius: 0;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      padding: 60px 0 40px;
    }
    .back-top {
      text-align: right;
    }
    @media(max-width:768px){ .footer-grid{grid-template-columns:1fr;} }