/* roulang page: index */
:root {
      --primary-cyan: #0A7E8C;
      --primary-dark: #086974;
      --accent-orange: #F15A24;
      --deep-slate: #1E2A2F;
      --fog-blue: #E8F4F6;
      --bg-light: #F8FAFB;
      --white: #FFFFFF;
      --border-light: #E2E8F0;
      --text-main: #1E2A2F;
      --text-muted: #475569;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.04);
      --shadow-hover: 0 8px 24px rgba(10, 126, 140, 0.08);
      --shadow-header: 0 1px 8px rgba(0,0,0,0.03);
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
      --transition-base: 0.2s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      line-height: 1.7;
      color: var(--text-main);
      background-color: var(--white);
      -webkit-font-smoothing: antialiased;
      overscroll-behavior: none;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, input {
      font-family: inherit;
      outline: none;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* Navigation */
    .top-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: var(--white);
      box-shadow: var(--shadow-header);
      z-index: 100;
      display: flex;
      align-items: center;
      backdrop-filter: blur(8px);
      background: rgba(255,255,255,0.92);
    }
    .nav-container {
      max-width: 1200px;
      width: 100%;
      margin: 0 auto;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 24px;
      position: relative;
    }
    .logobrand a {
      display: flex;
      align-items: baseline;
      gap: 4px;
      font-weight: 700;
      font-size: 22px;
      letter-spacing: -0.3px;
      color: var(--primary-cyan);
    }
    .logo-icon {
      font-size: 26px;
    }
    .desktop-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .desktop-links a {
      padding: 8px 2px;
      font-weight: 500;
      color: var(--text-muted);
      position: relative;
      transition: color var(--transition-base);
    }
    .desktop-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 3px;
      background: var(--primary-cyan);
      border-radius: 4px;
      transition: width 0.25s ease;
    }
    .desktop-links a:hover,
    .desktop-links a.active {
      color: var(--primary-cyan);
    }
    .desktop-links a.active::after {
      width: 100%;
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--deep-slate);
      cursor: pointer;
    }
    /* Mobile bottom nav */
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: var(--white);
      box-shadow: 0 -4px 14px rgba(0,0,0,0.06);
      z-index: 100;
      padding: 8px 14px;
      justify-content: space-around;
      backdrop-filter: blur(12px);
      background: rgba(255,255,255,0.94);
      border-top-left-radius: 18px;
      border-top-right-radius: 18px;
    }
    .mobile-bottom-nav a {
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 12px;
      color: var(--text-muted);
      font-weight: 500;
      padding: 4px 4px;
      transition: color 0.2s;
    }
    .mobile-bottom-nav a i {
      font-size: 20px;
      margin-bottom: 2px;
    }
    .mobile-bottom-nav a.active {
      color: var(--primary-cyan);
      font-weight: 600;
    }
    /* Hero */
    .hero-section {
      padding: 100px 0 90px;
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
      background-image: radial-gradient(circle at 80% 20%, #E8F4F6 0%, transparent 40%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .hero-text {
      flex: 1 1 55%;
    }
    .hero-visual {
      flex: 1 1 45%;
    }
    .hero-visual img {
      border-radius: 24px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.08);
      object-fit: cover;
      width: 100%;
      aspect-ratio: 1 / 1;
    }
    .hero-title {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--deep-slate);
      margin-bottom: 18px;
    }
    .hero-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 30px;
      max-width: 480px;
    }
    .btn-group {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      align-items: center;
      margin-bottom: 40px;
    }
    .btn {
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 15px;
      transition: all var(--transition-base);
      border: none;
      cursor: pointer;
      gap: 6px;
    }
    .btn-primary {
      background: var(--primary-cyan);
      color: white;
      box-shadow: 0 4px 10px rgba(10,126,140,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary-cyan);
      color: var(--primary-cyan);
    }
    .btn-secondary:hover {
      background: var(--fog-blue);
    }
    .trust-stats {
      display: flex;
      gap: 32px;
      flex-wrap: wrap;
    }
    .trust-stat-item {
      display: flex;
      align-items: baseline;
      gap: 6px;
    }
    .trust-number {
      font-size: 24px;
      font-weight: 700;
      color: var(--accent-orange);
    }
    .trust-desc {
      color: var(--text-muted);
      font-size: 14px;
      font-weight: 500;
    }
    /* Section spacing */
    section {
      padding: 90px 0;
      scroll-margin-top: 64px;
    }
    .section-title {
      text-align: center;
      margin-bottom: 16px;
      font-size: 32px;
      font-weight: 600;
      color: var(--deep-slate);
    }
    .section-sub {
      text-align: center;
      color: var(--text-muted);
      margin-bottom: 56px;
      font-size: 16px;
    }
    /* Cards grid */
    .grid-3, .grid-4 {
      display: grid;
      gap: 28px;
    }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    .card {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s, box-shadow 0.25s;
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .icon-wrap {
      width: 56px;
      height: 56px;
      background: var(--fog-blue);
      border-radius: 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary-cyan);
      font-size: 26px;
    }
    .card h3 {
      font-size: 19px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .service-card-img {
      aspect-ratio: 16/9;
      background: #dce9eb;
      border-radius: 10px;
      margin-bottom: 18px;
      overflow: hidden;
    }
    .service-card-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .text-link {
      color: var(--primary-cyan);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-top: 12px;
      transition: color 0.2s;
    }
    .text-link:hover { color: var(--primary-dark); }
    /* Data counters */
    .counter-grid {
      display: flex;
      justify-content: center;
      gap: 60px;
      flex-wrap: wrap;
    }
    .counter-item {
      text-align: center;
    }
    .big-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--primary-cyan);
      letter-spacing: -0.5px;
    }
    .unit { font-size: 28px; }
    .counter-label { color: var(--text-muted); margin-top: 6px; }
    /* FAQ */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .faq-item {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: 10px;
      transition: all 0.25s;
    }
    .faq-question {
      width: 100%;
      background: transparent;
      text-align: left;
      padding: 16px 20px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      border: none;
      font-size: 16px;
      cursor: pointer;
      color: var(--deep-slate);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: var(--fog-blue);
      padding: 0 20px;
    }
    .faq-item.active .faq-answer {
      max-height: 160px;
      padding: 18px 20px;
    }
    .faq-item.active {
      border-color: var(--primary-cyan);
    }
    /* CTA form */
    .cta-form {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 12px;
      margin-top: 28px;
    }
    .cta-input {
      padding: 14px 18px;
      border-radius: 8px;
      border: 1px solid var(--border-light);
      min-width: 260px;
      font-size: 15px;
      transition: border 0.2s;
    }
    .cta-input:focus {
      border-color: var(--primary-cyan);
      box-shadow: 0 0 0 3px rgba(10,126,140,0.15);
    }
    /* Footer */
    .page-footer {
      background: var(--deep-slate);
      color: #cfd8dc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
      margin-bottom: 40px;
    }
    .brand-name { color: white; font-size: 20px; font-weight: 700; margin-bottom: 12px; display: flex; align-items: center; gap: 4px;}
    .footer-links a { color: #b0bec5; display: block; margin-bottom: 8px; transition: color 0.2s;}
    .footer-links a:hover { color: white; }
    .copyright {
      border-top: 1px solid #33414a;
      padding-top: 24px;
      text-align: center;
      font-size: 14px;
      color: #90a4ae;
    }
    @media (max-width: 1024px) {
      .hero-grid { flex-direction: column; }
      .hero-visual img { aspect-ratio: 16/10; }
    }
    @media (max-width: 768px) {
      .desktop-links { display: none; }
      .menu-toggle { display: block; }
      .mobile-bottom-nav { display: flex; }
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .hero-title { font-size: 36px; }
      .section-title { font-size: 28px; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .counter-grid { gap: 40px; }
      section { padding: 70px 0; }
    }
    .hidden-mobile-menu { display: none; }