/* roulang page: index */
:root {
      --primary: #6C3CEC;
      --primary-dark: #5A2FD0;
      --primary-light: #F3EEFF;
      --secondary: #FF6B4A;
      --secondary-dark: #E85D3E;
      --success: #10B981;
      --warning: #F59E0B;
      --bg: #FAF9FC;
      --surface: #FFFFFF;
      --text: #1E1B2E;
      --text-secondary: #5A5671;
      --text-muted: #8E8A9E;
      --border: #E8E6F0;
      --radius-sm: 8px;
      --radius-md: 16px;
      --radius-lg: 24px;
      --radius-xl: 32px;
      --shadow-sm: 0 2px 12px rgba(108,60,236,0.06);
      --shadow-md: 0 8px 28px rgba(108,60,236,0.12);
      --shadow-lg: 0 16px 40px rgba(108,60,236,0.18);
      --font-stack: "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
      --font-number: "Inter", "SF Pro Text", "Roboto", system-ui, sans-serif;
      --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

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

    body {
      font-family: var(--font-stack);
      background: var(--bg);
      color: var(--text);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
      overflow-x: hidden;
    }

    a { text-decoration: none; color: inherit; }
    img { max-width: 100%; height: auto; display: block; }
    button, .btn { cursor: pointer; border: none; font-family: inherit; }
    ul, ol { list-style: none; }

    .container {
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* header / nav */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: background var(--transition), box-shadow var(--transition);
      background: transparent;
    }
    .site-header.scrolled {
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 2px 20px rgba(0,0,0,0.06);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 68px;
    }
    .logo {
      font-size: 1.4rem;
      font-weight: 700;
      color: #fff;
      letter-spacing: 0.02em;
      display: flex;
      align-items: center;
      gap: 8px;
      transition: color var(--transition);
    }
    .scrolled .logo { color: var(--text); }
    .logo i { font-size: 1.6rem; color: var(--secondary); }

    .nav-menu { display: flex; align-items: center; gap: 32px; }
    .nav-menu a {
      font-size: 0.95rem;
      font-weight: 500;
      color: rgba(255,255,255,0.9);
      transition: color var(--transition);
      position: relative;
    }
    .scrolled .nav-menu a { color: var(--text-secondary); }
    .nav-menu a:hover { color: var(--secondary); }
    .scrolled .nav-menu a:hover { color: var(--primary); }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      color: #fff;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 14px rgba(108,60,236,0.3);
      transition: transform var(--transition), box-shadow var(--transition), opacity var(--transition);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 22px rgba(108,60,236,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid rgba(255,255,255,0.8);
      color: #fff;
      font-weight: 600;
      padding: 10px 26px;
      border-radius: var(--radius-sm);
      transition: all var(--transition);
    }
    .scrolled .btn-outline { border-color: var(--primary); color: var(--primary); }
    .btn-outline:hover {
      background: rgba(255,255,255,0.15);
      border-color: #fff;
    }
    .scrolled .btn-outline:hover {
      background: var(--primary-light);
      border-color: var(--primary);
    }

    .mobile-toggle {
      display: none;
      background: none;
      font-size: 1.8rem;
      color: #fff;
    }
    .scrolled .mobile-toggle { color: var(--text); }

    /* hero */
    .hero {
      padding: 140px 0 80px;
      background: linear-gradient(135deg, #6C3CEC 0%, #A855F7 40%, #FF6B4A 100%);
      position: relative;
      overflow: hidden;
      min-height: 90vh;
      display: flex;
      align-items: center;
    }
    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.15;
      mix-blend-mode: overlay;
    }
    .hero .container {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      position: relative;
      z-index: 2;
    }
    .hero-content h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.25;
      color: #fff;
      margin-bottom: 20px;
      letter-spacing: -0.02em;
    }
    .hero-content .subtitle {
      font-size: 1.15rem;
      color: rgba(255,255,255,0.85);
      margin-bottom: 32px;
      line-height: 1.6;
    }
    .hero-actions {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      margin-bottom: 36px;
    }
    .hero-badges {
      display: flex;
      flex-wrap: wrap;
      gap: 20px;
    }
    .badge-chip {
      background: rgba(255,255,255,0.18);
      backdrop-filter: blur(8px);
      color: #fff;
      padding: 8px 18px;
      border-radius: 40px;
      font-size: 0.9rem;
      font-weight: 500;
      display: flex;
      align-items: center;
      gap: 6px;
      border: 1px solid rgba(255,255,255,0.25);
    }
    .badge-chip i { color: var(--warning); }

    .hero-visual {
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .mockup-frame {
      background: rgba(255,255,255,0.08);
      backdrop-filter: blur(10px);
      border-radius: 36px;
      padding: 18px;
      border: 1px solid rgba(255,255,255,0.2);
      box-shadow: 0 30px 60px rgba(0,0,0,0.25);
      transform: perspective(800px) rotateY(-4deg) rotateX(2deg);
      transition: transform 0.4s;
    }
    .mockup-frame img {
      border-radius: 24px;
      width: 260px;
    }

    /* sections */
    section { padding: 80px 0; }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 2.2rem;
      font-weight: 600;
      color: var(--text);
      margin-bottom: 12px;
    }
    .section-title p {
      font-size: 1rem;
      color: var(--text-secondary);
      max-width: 600px;
      margin: 0 auto;
    }

    /* pain points */
    .pain-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .pain-card {
      background: #F2EEF9;
      border-radius: var(--radius-lg);
      padding: 28px;
      display: flex;
      gap: 18px;
      align-items: flex-start;
      transition: all var(--transition);
      border: 1px solid transparent;
    }
    .pain-card:hover {
      background: #fff;
      border-color: var(--border);
      box-shadow: var(--shadow-md);
    }
    .pain-icon {
      font-size: 2rem;
      color: var(--primary);
      background: #fff;
      width: 52px;
      height: 52px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-md);
      flex-shrink: 0;
    }
    .pain-text h3 { font-size: 1.15rem; margin-bottom: 6px; }
    .pain-text p { color: var(--text-muted); font-size: 0.9rem; }

    /* solutions */
    .solution-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .solution-card {
      background: var(--surface);
      border-radius: var(--radius-lg);
      padding: 32px 28px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      transition: all var(--transition);
      border: 1px solid var(--border);
    }
    .solution-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .sol-icon-row {
      display: flex;
      align-items: center;
      gap: 16px;
      margin-bottom: 18px;
    }
    .sol-icon {
      width: 56px;
      height: 56px;
      background: var(--primary-light);
      border-radius: var(--radius-md);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.8rem;
      color: var(--primary);
    }
    .sol-badge {
      background: var(--secondary);
      color: #fff;
      font-size: 0.75rem;
      font-weight: 600;
      padding: 5px 12px;
      border-radius: 20px;
      font-family: var(--font-number);
    }
    .solution-card h3 { font-size: 1.3rem; margin-bottom: 8px; }
    .solution-card p { color: var(--text-secondary); font-size: 0.95rem; flex: 1; }

    /* download */
    .download-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .dl-card {
      background: #fff;
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      text-align: center;
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      transition: all var(--transition);
    }
    .dl-card:hover { box-shadow: var(--shadow-md); transform: translateY(-4px); }
    .dl-icon {
      font-size: 2.8rem;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .dl-card.android .dl-icon { color: #3DDC84; }
    .dl-card.ios .dl-icon { color: #000; }
    .dl-card.pc .dl-icon { color: #0078D4; }
    .dl-card h3 { font-size: 1.25rem; margin-bottom: 8px; }
    .dl-version {
      font-size: 0.8rem;
      color: var(--text-muted);
      margin-bottom: 20px;
      font-family: var(--font-number);
    }
    .dl-btn {
      width: 100%;
      background: var(--primary);
      color: #fff;
      padding: 12px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all var(--transition);
    }
    .dl-btn:hover { background: var(--primary-dark); }
    .dl-safe {
      margin-top: 12px;
      font-size: 0.8rem;
      color: var(--success);
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 5px;
    }

    /* stats & testimonial */
    .stats-band {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 40px;
      margin-bottom: 48px;
    }
    .stat-item {
      text-align: center;
      font-family: var(--font-number);
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      font-size: 0.9rem;
      color: var(--text-muted);
    }
    .testimonial-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .testimonial-card {
      background: #fff;
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
    }
    .testimonial-card .stars { color: var(--warning); margin-bottom: 8px; }
    .testimonial-text { font-size: 0.95rem; color: var(--text-secondary); margin-bottom: 16px; }
    .testimonial-user {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .avatar {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      background: var(--primary-light);
      overflow: hidden;
    }

    /* FAQ */
    .faq-wrapper {
      display: grid;
      grid-template-columns: 240px 1fr;
      gap: 48px;
      align-items: start;
    }
    .faq-index {
      background: #fff;
      border-radius: var(--radius-lg);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      position: sticky;
      top: 100px;
    }
    .faq-index a {
      display: block;
      padding: 10px 14px;
      font-size: 0.95rem;
      border-radius: var(--radius-sm);
      color: var(--text-secondary);
      transition: 0.2s;
      margin-bottom: 4px;
    }
    .faq-index a:hover, .faq-index a.active {
      background: var(--primary-light);
      color: var(--primary);
      font-weight: 600;
    }
    .faq-details details {
      background: #fff;
      border-radius: var(--radius-md);
      margin-bottom: 16px;
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      transition: all var(--transition);
    }
    .faq-details summary {
      padding: 20px 24px;
      font-weight: 600;
      font-size: 1.05rem;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      list-style: none;
    }
    .faq-details summary::-webkit-details-marker { display: none; }
    .faq-details summary i { transition: transform 0.2s; color: var(--primary); }
    .faq-details[open] summary i { transform: rotate(45deg); }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-secondary);
      font-size: 0.95rem;
      line-height: 1.7;
    }

    /* final CTA */
    .cta-band {
      background: linear-gradient(135deg, var(--primary), #A855F7);
      border-radius: var(--radius-xl);
      padding: 70px 40px;
      text-align: center;
      color: #fff;
      margin: 40px auto;
      max-width: 1000px;
    }
    .cta-band h2 { font-size: 2rem; margin-bottom: 12px; }
    .cta-band p { margin-bottom: 28px; opacity: 0.9; }

    /* footer */
    .site-footer {
      background: #1E1B2E;
      color: #ccc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-grid h4 { color: #fff; margin-bottom: 16px; font-size: 1rem; }
    .footer-grid a { color: #aaa; font-size: 0.9rem; display: block; margin-bottom: 8px; transition: color 0.2s; }
    .footer-grid a:hover { color: var(--secondary); }
    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
      text-align: center;
      font-size: 0.8rem;
      color: #777;
    }

    /* mobile float CTA */
    .mobile-float-cta {
      display: none;
      position: fixed;
      bottom: 20px;
      left: 20px;
      right: 20px;
      z-index: 999;
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      color: #fff;
      padding: 14px;
      border-radius: 50px;
      text-align: center;
      font-weight: 700;
      box-shadow: 0 10px 30px rgba(108,60,236,0.5);
    }

    @media (max-width: 1024px) {
      .hero .container { grid-template-columns: 1fr; text-align: center; }
      .hero-visual { order: -1; }
      .mockup-frame img { width: 200px; }
      .hero-content h1 { font-size: 2.4rem; }
      .pain-grid, .solution-grid, .download-grid, .testimonial-grid { grid-template-columns: 1fr; }
      .faq-wrapper { grid-template-columns: 1fr; }
      .faq-index { position: static; display: flex; flex-wrap: wrap; gap: 8px; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }

    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .mobile-toggle { display: block; }
      .hero { padding: 120px 0 60px; min-height: auto; }
      .hero-content h1 { font-size: 2rem; }
      .stats-band { gap: 24px; }
      .stat-number { font-size: 2rem; }
    }

    @media (max-width: 520px) {
      .container { padding: 0 16px; }
      .mobile-float-cta { display: block; }
      .hero-actions { flex-direction: column; }
      .btn-primary, .btn-outline { width: 100%; justify-content: center; }
      .footer-grid { grid-template-columns: 1fr; }
    }

    /* mobile nav open */
    .mobile-nav-open .nav-menu {
      display: flex;
      flex-direction: column;
      position: fixed;
      top: 68px;
      left: 0;
      width: 100%;
      background: #fff;
      padding: 32px;
      box-shadow: var(--shadow-lg);
      gap: 20px;
    }
    .mobile-nav-open .nav-menu a { color: var(--text); }