:root {
      --primary: #0b1a2e;        /* deep navy – main background */
      --primary-light: #13263f;  /* cards / sections */
      --secondary: #2b6ef0;      /* vibrant blue – buttons, accents */
      --secondary-dark: #1a56c9;
      --accent: #00c3ff;          /* light blue highlights */
      --text-light: #f0f6ff;
      --text-muted: #a0b3d9;
      --border-blue: rgba(43, 110, 240, 0.25);
      --white: #ffffff;
      --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--primary);
      color: var(--text-light);
      line-height: 1.6;
    }

    .container {
      width: 90%;
      max-width: 1280px;
      margin: 0 auto;
    }

    /* skip link */
    .skip-to-content {
      position: absolute;
      left: -999px;
      top: 0;
      background: var(--secondary);
      color: white;
      padding: 0.8rem;
      z-index: 999;
    }
    .skip-to-content:focus { left: 0; }

    /* header – exactly matching qr.devshield.tech style + hamburger */
    .site-header {
      background: rgba(11, 26, 46, 0.95);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--border-blue);
      padding: 0.8rem 0;
      position: sticky;
      top: 0;
      z-index: 100;
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
    }

    .logo a {
      font-size: 2rem;
      font-weight: 700;
      color: white;
      text-decoration: none;
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--accent);
      font-weight: 300;
    }
    .logo .dot {
      color: var(--secondary);
    }

    /* navigation – desktop */
    .nav-links {
      display: flex;
      gap: 2.2rem;
      align-items: center;
    }
    .nav-links a {
      color: var(--text-muted);
      text-decoration: none;
      font-weight: 500;
      transition: color 0.2s;
      font-size: 1rem;
    }
    .nav-links a:hover { color: white; }

    .btn {
      display: inline-block;
      background: transparent;
      border: 1.5px solid var(--border-blue);
      padding: 0.6rem 1.5rem;
      border-radius: 40px;
      font-weight: 600;
      text-decoration: none;
      color: white;
      transition: 0.2s;
      font-size: 0.95rem;
    }
    .btn-primary {
      background: var(--secondary);
      border-color: var(--secondary);
      color: white;
      box-shadow: 0 8px 20px -8px var(--secondary);
    }
    .btn-primary:hover {
      background: var(--secondary-dark);
      border-color: var(--secondary-dark);
      transform: scale(1.02);
    }
    .btn-outline {
      border-color: var(--secondary);
      color: var(--secondary);
    }
    .btn-outline:hover {
      background: var(--secondary);
      color: white;
    }

    /* hamburger menu - hidden on desktop */
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 10px 5px;
      z-index: 200;
    }
    .hamburger span {
      width: 28px;
      height: 2px;
      background: var(--accent);
      margin: 4px 0;
      transition: 0.3s;
      border-radius: 2px;
    }
    /* mobile nav */
    .mobile-nav {
      display: none;
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: var(--primary-light);
      backdrop-filter: blur(12px);
      padding: 2rem;
      flex-direction: column;
      align-items: center;
      gap: 1.8rem;
      border-bottom: 1px solid var(--border-blue);
      z-index: 99;
      transform: translateY(-150%);
      transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1);
      box-shadow: 0 30px 40px -20px black;
    }
    .mobile-nav.active {
      transform: translateY(0);
    }
    .mobile-nav a {
      color: var(--text-light);
      text-decoration: none;
      font-size: 1.3rem;
      font-weight: 500;
    }
    .mobile-nav .btn {
      width: 80%;
      text-align: center;
      margin: 0.2rem 0;
    }

    /* hero – blue gradient like qr.devshield */
    .hero {
      padding: 4rem 0 3rem;
      background: radial-gradient(ellipse at 70% 30%, #1a3d6e, var(--primary) 70%);
    }
    .hero-content {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 3rem;
      align-items: center;
    }
    .hero-text h1 {
      font-size: 3.3rem;
      line-height: 1.2;
      margin-bottom: 1.5rem;
      font-weight: 700;
    }
    .hero-text h1 span {
      color: var(--accent);
      border-bottom: 3px solid var(--secondary);
      display: inline-block;
      padding-bottom: 5px;
    }
    .hero-subtitle {
      color: var(--accent);
      text-transform: uppercase;
      letter-spacing: 2px;
      font-weight: 600;
      margin-bottom: 0.5rem;
      font-size: 0.9rem;
    }
    .hero-cta {
      margin: 2.5rem 0 1.5rem;
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }

    /* stats cards (blueish) */
    .stats-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      gap: 2rem;
      margin: 3rem 0;
      background: var(--primary-light);
      padding: 2rem 2.5rem;
      border-radius: 48px;
      border: 1px solid var(--border-blue);
      box-shadow: 0 20px 40px -20px #00000080;
    }
    .stat-item {
      text-align: center;
      flex: 1;
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: white;
      line-height: 1.2;
    }
    .stat-label {
      text-transform: uppercase;
      font-size: 0.85rem;
      color: var(--text-muted);
      letter-spacing: 0.5px;
    }

    /* section titles – like qr.devshield */
    .section-title {
      text-align: center;
      margin: 4rem 0 2.5rem;
    }
    .section-title h2 {
      font-size: 2.8rem;
      color: white;
      font-weight: 600;
    }
    .section-title p {
      color: var(--text-muted);
      font-size: 1.2rem;
      max-width: 700px;
      margin: 0.5rem auto 0;
    }

    /* cards grid – glassmorphism blue */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 2rem;
    }
    .card {
      background: var(--primary-light);
      border: 1px solid var(--border-blue);
      border-radius: 32px;
      padding: 2.2rem 1.8rem;
      transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
      backdrop-filter: blur(4px);
    }
    .card:hover {
      border-color: var(--secondary);
      box-shadow: 0 20px 30px -20px #2b6ef0;
      transform: translateY(-6px);
    }
    .card-icon {
      font-size: 2.8rem;
      margin-bottom: 1.2rem;
      color: var(--accent);
    }
    .card h3 {
      font-size: 1.8rem;
      margin-bottom: 1rem;
      font-weight: 600;
    }
    .card p {
      color: var(--text-muted);
    }

    /* warning box – blue alert */
    .warning-box {
      background: rgba(43, 110, 240, 0.08);
      border-left: 5px solid var(--secondary);
      padding: 2rem;
      border-radius: 24px;
      margin: 2.5rem 0;
      font-weight: 500;
      backdrop-filter: blur(4px);
    }

    /* pricing cards – exactly like qr.devshield.tech */
    .pricing-cards {
      display: flex;
      flex-wrap: wrap;
      gap: 2rem;
      justify-content: center;
      margin-top: 2rem;
    }
    .pricing-card {
      background: var(--primary-light);
      border: 1px solid var(--border-blue);
      border-radius: 32px;
      padding: 2.5rem 2rem;
      flex: 1 1 280px;
      max-width: 330px;
      display: flex;
      flex-direction: column;
      transition: all 0.2s;
    }
    .pricing-card.popular {
      border-color: var(--secondary);
      box-shadow: 0 0 30px -10px var(--secondary);
      transform: scale(1.02);
    }
    .pricing-name {
      font-size: 2rem;
      font-weight: 600;
      color: white;
    }
    .pricing-price {
      font-size: 3rem;
      font-weight: 700;
      color: white;
      margin: 0.5rem 0;
    }
    .pricing-price small {
      font-size: 1rem;
      font-weight: 400;
      color: var(--text-muted);
    }
    .pricing-features {
      list-style: none;
      margin: 1.5rem 0 2rem;
      flex-grow: 1;
    }
    .pricing-features li {
      padding: 0.6rem 0;
      display: flex;
      align-items: center;
      gap: 0.7rem;
      border-bottom: 1px solid rgba(255,255,255,0.05);
    }
    .pricing-features i {
      color: var(--accent);
      width: 22px;
      font-size: 1.1rem;
    }
    .pricing-features .disabled i {
      color: #4b587c;
    }

    /* donation box */
    .donation-box {
      background: var(--primary-light);
      border: 1px solid var(--border-blue);
      border-radius: 48px;
      padding: 2.5rem;
      text-align: center;
      max-width: 700px;
      margin: 3rem auto;
    }
    .usdt-address {
      background: var(--primary);
      padding: 1rem 1.5rem;
      border-radius: 60px;
      font-family: monospace;
      font-size: 1.3rem;
      border: 1px solid var(--secondary);
      color: var(--accent);
      word-break: break-all;
      margin: 1.5rem 0;
    }

    /* footer – grid layout */
    .site-footer {
      background: var(--primary-light);
      border-top: 1px solid var(--border-blue);
      padding: 3rem 0;
      margin-top: 4rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
      gap: 2rem;
      margin-bottom: 2rem;
    }
    .footer-col h4 {
      color: white;
      font-size: 1.2rem;
      margin-bottom: 1rem;
    }
    .footer-col h4 span { color: var(--accent); }
    .footer-col p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.6; }
    .footer-col a {
      display: block;
      color: var(--text-muted);
      text-decoration: none;
      font-size: 0.9rem;
      padding: 0.3rem 0;
      transition: color 0.2s;
    }
    .footer-col a:hover { color: var(--accent); }
    .footer-wallet {
      background: var(--primary);
      padding: 0.8rem;
      border-radius: 12px;
      font-family: monospace;
      font-size: 0.85rem;
      color: var(--accent);
      word-break: break-all;
      border: 1px solid var(--border-blue);
    }
    .footer-bottom {
      border-top: 1px solid var(--border-blue);
      padding-top: 1.5rem;
      text-align: center;
      color: var(--text-muted);
      font-size: 0.85rem;
    }

    /* responsive + hamburger */
    @media (max-width: 900px) {
      .hero-content { grid-template-columns: 1fr; text-align: center; }
      .hero-cta { justify-content: center; }

      /* hide desktop nav, show hamburger */
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-nav {
        display: flex; /* flex container but hidden via transform */
      }
    }
    @media (max-width: 600px) {
      .hero-text h1 { font-size: 2.5rem; }
      .section-title h2 { font-size: 2rem; }
      .stats-grid { flex-direction: column; align-items: center; }
    }

    /* fade animations (same as qr.devshield) */
    .fade-in {
      opacity: 1;
      transform: translateY(0);
      transition: opacity 0.7s cubic-bezier(0.2, 0.9, 0.3, 1), transform 0.7s ease;
    }
    .fade-in.visible {
      opacity: 1;
      transform: translateY(0);
    }
    .delay-1 { transition-delay: 0.1s; }
    .delay-2 { transition-delay: 0.2s; }
    .delay-3 { transition-delay: 0.3s; }