/* roulang page: index */
/* ----- DESIGN SYSTEM & RESET ----- */
    :root {
      --primary: #1A1A2E;
      --accent: #FF6B35;
      --bg: #F8F9FA;
      --card: #FFFFFF;
      --text-primary: #1A1A2E;
      --text-secondary: #5A6070;
      --text-muted: #9CA3AF;
      --border: #E5E7EB;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
      --font-stack: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --transition: 0.2s ease;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-stack);
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img { max-width: 100%; height: auto; display: block; }
    a { text-decoration: none; color: inherit; }
    ul, ol { list-style: none; }

    .container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

    h1, h2, h3, h4 { font-weight: 600; }
    h1 { font-size: 48px; letter-spacing: -0.5px; line-height: 1.2; font-weight: 700; }
    h2 { font-size: 36px; letter-spacing: -0.3px; line-height: 1.3; margin-bottom: 16px; }
    h3 { font-size: 22px; line-height: 1.4; margin-bottom: 12px; }
    .section { padding: 120px 0; }
    .bg-white { background-color: var(--card); }
    .bg-light { background-color: var(--bg); }
    .text-muted { color: var(--text-muted); }
    .text-secondary { color: var(--text-secondary); }
    .text-accent { color: var(--accent); }
    .bold { font-weight: 700; }

    /* Buttons */
    .btn {
      display: inline-flex; align-items: center; justify-content: center;
      padding: 14px 32px; border-radius: var(--radius-sm); font-weight: 600;
      font-size: 16px; letter-spacing: 0.5px; cursor: pointer;
      transition: all var(--transition); border: 2px solid transparent;
      outline: none; text-align: center;
    }
    .btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
    .btn-primary {
      background-color: var(--accent); color: #fff; border-color: var(--accent);
    }
    .btn-primary:hover {
      background-color: #E55A2B; border-color: #E55A2B;
      transform: translateY(-2px); box-shadow: var(--shadow-md);
    }
    .btn-primary:active { transform: scale(0.98); }
    .btn-outline {
      background: transparent; border: 2px solid var(--primary); color: var(--primary);
    }
    .btn-outline:hover {
      background: var(--primary); color: #fff; border-color: var(--primary);
      transform: translateY(-2px); box-shadow: var(--shadow-md);
    }
    .btn-outline:active { transform: scale(0.98); }
    .btn-white {
      background: #fff; color: var(--accent); border-color: #fff;
    }
    .btn-white:hover {
      background: #f4f4f4; border-color: #f4f4f4; transform: translateY(-2px); box-shadow: 0 8px 20px rgba(0,0,0,0.1);
    }

    /* Text link with animation */
    .link-accent {
      color: var(--accent); font-weight: 600; position: relative;
      white-space: nowrap;
    }
    .link-accent::after {
      content: ''; position: absolute; left: 0; bottom: -2px; width: 0; height: 2px;
      background: var(--accent); transition: width 0.25s ease;
    }
    .link-accent:hover::after { width: 100%; }

    /* Card base */
    .card {
      background: var(--card); border-radius: var(--radius-md);
      padding: 32px; box-shadow: var(--shadow-sm);
      transition: box-shadow 0.2s ease, transform 0.2s ease;
    }
    .card:hover { box-shadow: var(--shadow-md); }

    /* NAV */
    .site-header {
      position: sticky; top: 0; z-index: 50; background: #fff;
      box-shadow: 0 1px 8px rgba(0,0,0,0.04); transition: box-shadow 0.2s;
    }
    .header-inner {
      display: flex; align-items: center; justify-content: space-between;
      height: 72px; max-width: 1200px; margin: 0 auto; padding: 0 24px;
    }
    .logo {
      display: flex; align-items: baseline; gap: 8px; font-weight: 700;
      font-size: 24px; color: var(--primary); white-space: nowrap;
    }
    .logo span { font-size: 0.9rem; color: var(--text-muted); font-weight: 400; }
    .nav-menu { display: flex; gap: 32px; align-items: center; }
    .nav-menu a {
      font-weight: 500; font-size: 16px; color: var(--text-secondary);
      transition: color 0.15s; padding: 8px 0; border-bottom: 2px solid transparent;
    }
    .nav-menu a:hover, .nav-menu a.active { color: var(--accent); border-bottom-color: var(--accent); }
    .menu-toggle { display: none; background: none; border: none; font-size: 28px; color: var(--primary); cursor: pointer; }

    /* Mobile nav panel */
    .mobile-nav {
      position: fixed; top: 0; left: 0; width: 100%; height: 100%;
      background: var(--primary); z-index: 100; display: flex; flex-direction: column;
      align-items: center; justify-content: center; gap: 32px;
      transform: translateX(100%); transition: transform 0.3s ease;
    }
    .mobile-nav.open { transform: translateX(0); }
    .mobile-nav a {
      color: #fff; font-size: 22px; font-weight: 500;
    }
    .mobile-close {
      position: absolute; bottom: 60px; font-size: 28px; background: none;
      border: none; color: #fff; cursor: pointer;
    }

    /* Hero */
    .hero-grid {
      display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center;
      position: relative;
    }
    .hero-left { max-width: 540px; }
    .hero-sub { font-size: 18px; color: var(--text-secondary); margin: 24px 0 32px; }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .client-proof { display: flex; align-items: center; gap: 24px; margin-top: 40px; color: var(--text-muted); font-size: 14px; }
    .logo-strip { display: flex; gap: 16px; filter: grayscale(1); opacity: 0.7; }
    .hero-right img { border-radius: var(--radius-md); box-shadow: var(--shadow-sm); width: 100%; }
    .hero-bg-glow {
      position: absolute; top: -80px; right: -20px;
      width: 500px; height: 500px;
      background: radial-gradient(circle, rgba(255,107,53,0.06) 0%, transparent 70%);
      pointer-events: none; z-index: 0;
    }

    /* Value cards */
    .cards-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .card-accent-left { border-left: 4px solid var(--accent); padding-left: 24px; }
    .card-icon { width: 48px; height: 48px; margin-bottom: 20px; color: var(--accent); }
    .big-number { font-size: 36px; font-weight: 700; color: var(--accent); margin-top: 16px; }
    .quote-icon { font-size: 40px; color: var(--accent); opacity: 0.6; margin-bottom: 12px; }

    /* Solutions alternating */
    .solution-row {
      display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center;
      margin-bottom: 80px;
    }
    .solution-row.reverse { direction: rtl; }
    .solution-row.reverse .solution-text { direction: ltr; }
    .solution-img img { border-radius: var(--radius-md); box-shadow: var(--shadow-sm); }

    /* Scenario cards */
    .scroll-wrapper { display: flex; gap: 24px; overflow-x: auto; padding-bottom: 16px; scroll-snap-type: x mandatory; }
    .scroll-card { min-width: 280px; scroll-snap-align: start; }
    .scroll-card img { border-radius: var(--radius-md); transition: transform 0.2s; }
    .scroll-card:hover img { transform: scale(1.02); }
    .scroll-controls { display: flex; justify-content: flex-end; gap: 12px; margin-top: 24px; }
    .scroll-btn {
      width: 44px; height: 44px; border-radius: 50%; background: var(--accent);
      color: #fff; border: none; font-size: 20px; cursor: pointer; display: flex;
      align-items: center; justify-content: center;
    }

    /* Stats + quote */
    .stats-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; }
    .stat-item h3 { font-size: 48px; color: var(--accent); margin-bottom: 8px; }
    .testimonial blockquote {
      font-size: 18px; font-style: italic; color: var(--text-secondary);
      border-left: 4px solid var(--accent); padding-left: 24px;
    }

    /* FAQ */
    .faq-list { max-width: 800px; margin: 0 auto; }
    .faq-item { border-bottom: 1px solid var(--border); }
    .faq-question {
      display: flex; justify-content: space-between; align-items: center;
      padding: 20px 0; cursor: pointer; font-weight: 600; font-size: 18px;
    }
    .faq-icon { font-size: 22px; color: var(--accent); transition: transform 0.2s; }
    .faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease, padding 0.3s; color: var(--text-secondary); }
    .faq-item.active .faq-answer { max-height: 200px; padding-bottom: 20px; }
    .faq-item.active .faq-icon { transform: rotate(45deg); }

    /* Final CTA */
    .cta-band {
      background: linear-gradient(135deg, #FF6B35 0%, #FF8C5A 100%);
      border-radius: var(--radius-lg); text-align: center; padding: 80px 24px;
      position: relative; overflow: hidden;
    }
    .cta-band h2 { color: #fff; }
    .cta-band p { color: rgba(255,255,255,0.9); font-size: 18px; margin-bottom: 32px; }
    .wave-bg {
      position: absolute; top: 0; left: 0; width: 100%; height: 100%;
      background: radial-gradient(circle at 30% 40%, rgba(255,255,255,0.08) 0%, transparent 40%);
      pointer-events: none;
    }

    /* Footer */
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; padding-bottom: 48px; }
    .footer-logo { font-size: 24px; font-weight: 700; }
    .social-icons { display: flex; gap: 16px; margin-top: 16px; }
    .social-icons a { color: var(--text-muted); font-size: 20px; transition: color 0.2s; }
    .social-icons a:hover { color: var(--accent); }
    .footer-col h4 { margin-bottom: 16px; font-size: 16px; }
    .footer-col a { display: block; color: var(--text-secondary); margin-bottom: 10px; font-size: 15px; }
    .copyright {
      background: var(--primary); color: #fff; text-align: center;
      padding: 20px 24px; font-size: 14px;
    }

    @media (max-width: 1024px) {
      h1 { font-size: 38px; }
      h2 { font-size: 30px; }
    }
    @media (max-width: 768px) {
      .section { padding: 80px 0; }
      .nav-menu { display: none; }
      .menu-toggle { display: block; }
      .hero-grid, .stats-grid, .solution-row, .cards-grid, .footer-grid {
        grid-template-columns: 1fr; gap: 32px;
      }
      .hero-right { order: -1; }
      .solution-row.reverse { direction: ltr; }
      .scroll-wrapper { overflow-x: visible; flex-direction: column; }
      .scroll-controls { display: none; }
      h1 { font-size: 34px; }
      h2 { font-size: 28px; }
    }