/* =========================================== */
    /* FURPS: SUPPORTABILITY - CSS Variables System */
    /* =========================================== */
    :root {
      /* Color System */
      --primary: #ffcc00;
      --secondary: #1a2a6c;
      --accent: #f1faee;
      --light: #a8dadc;
      --dark: #457b9d;
      --danger: #e63946;
      --success: #2a9d8f;
      --warning: #ff9800;
      --text: #333;
      --white: #ffffff;
      --gray: #f8f9fa;
      --dark-gray: #6c757d;
      
      /* Spacing System */
      --space-xs: 4px;
      --space-sm: 8px;
      --space-md: 16px;
      --space-lg: 24px;
      --space-xl: 32px;
      --space-xxl: 48px;
      
      /* Typography System */
      --font-size-xs: 0.75rem;
      --font-size-sm: 0.875rem;
      --font-size-md: 1rem;
      --font-size-lg: 1.125rem;
      --font-size-xl: 1.25rem;
      --font-size-xxl: 1.5rem;
      --font-size-xxxl: 2rem;
      
      /* Effects System */
      --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
      --shadow-hover: 0 15px 40px rgba(0, 0, 0, 0.2);
      --shadow-focus: 0 0 0 3px rgba(255, 204, 0, 0.2);
      --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
      --border-radius: 10px;
      --border-radius-lg: 20px;
      
      /* Z-index System */
      --z-dropdown: 1000;
      --z-modal: 1050;
      --z-tooltip: 1070;
    }

    /* =========================================== */
    /* FURPS: RELIABILITY & USABILITY - Base Styles */
    /* =========================================== */
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    /* FURPS: USABILITY - Focus management */
    :focus {
      outline: 3px solid var(--primary);
      outline-offset: 2px;
    }

    :focus:not(:focus-visible) {
      outline: none;
    }

    :focus-visible {
      outline: 3px solid var(--primary);
      outline-offset: 2px;
    }

    /* FURPS: USABILITY - Reduced motion preferences */
    @media (prefers-reduced-motion: reduce) {
      *,
      *::before,
      *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
      }
    }

    body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
      background: radial-gradient(circle at top left, #1a2a6c 0, #020617 45%, #000 100%);
      color: var(--text);
      min-height: 100vh;
      display: flex;
      flex-direction: column;
      line-height: 1.6;
      font-size: var(--font-size-md);
    }

    /* FURPS: USABILITY - Skip to content for screen readers */
    .skip-to-content {
      position: absolute;
      top: -40px;
      left: 0;
      background: var(--primary);
      color: var(--secondary);
      padding: var(--space-sm) var(--space-md);
      text-decoration: none;
      font-weight: 600;
      z-index: var(--z-tooltip);
      border-radius: var(--border-radius);
    }

    .skip-to-content:focus {
      top: var(--space-sm);
      outline: 3px solid var(--secondary);
    }

    /* =========================================== */
    /* FURPS: USABILITY - Component Styles */
    /* =========================================== */
    .header {
      text-align: center;
      margin-bottom: var(--space-xl);
      width: 100%;
      max-width: 1000px;
    }

    .logo {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: var(--space-md);
      margin-bottom: var(--space-md);
    }

    .logo-icon {
      font-size: 2.5rem;
      color: var(--primary);
      transform: rotate(-15deg);
      animation: float 3s ease-in-out infinite;
    }

    @keyframes float {
      0%, 100% { transform: translateY(0) rotate(-15deg); }
      50% { transform: translateY(-10px) rotate(-15deg); }
    }

    .logo-text {
      font-size: var(--font-size-xxxl);
      font-weight: 900;
      text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
      background: linear-gradient(to right, var(--primary), #ffffff);
      -webkit-background-clip: text;
      background-clip: text;
      color: transparent;
      letter-spacing: 1px;
    }

    .container {
      max-width: 1000px;
      width: 100%;
      margin: auto;
      padding: var(--space-xxl);
      border-radius: var(--border-radius-lg);
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      box-shadow: var(--shadow);
      border: 1px solid rgba(255, 255, 255, 0.2);
      animation: slideInUp 0.5s ease;
    }

    @keyframes slideInUp {
      from { 
        opacity: 0; 
        transform: translateY(30px); 
      }
      to { 
        opacity: 1; 
        transform: translateY(0); 
      }
    }

    h1 {
      text-align: center;
      color: var(--secondary);
      margin-bottom: var(--space-sm);
      font-size: var(--font-size-xxxl);
      text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.1);
    }

    h2 {
      text-align: center;
      color: var(--dark);
      margin-bottom: var(--space-xl);
      font-size: var(--font-size-xl);
      font-weight: 500;
    }

    .section-title {
      font-size: var(--font-size-xxl);
      margin-top: var(--space-xxl);
      margin-bottom: var(--space-lg);
      font-weight: 700;
      padding-bottom: var(--space-sm);
      border-bottom: 3px solid var(--primary);
      color: var(--secondary);
      position: relative;
    }

    .section-title::after {
      content: '';
      position: absolute;
      bottom: -3px;
      left: 0;
      width: 100px;
      height: 3px;
      background: var(--secondary);
    }

    .form-group {
      margin-bottom: var(--space-lg);
    }

    /* FURPS: USABILITY - Improved label accessibility */
    label {
      display: block;
      margin-bottom: var(--space-sm);
      font-weight: 600;
      color: var(--secondary);
      font-size: var(--font-size-md);
    }

    .required::after {
      content: " *";
      color: var(--danger);
    }

    .input-group {
      position: relative;
    }

    /* FURPS: USABILITY - Consistent input styling */
    input[type="text"],
    input[type="email"],
    input[type="tel"],
    input[type="number"],
    input[type="date"],
    select,
    textarea {
      width: 100%;
      padding: var(--space-md);
      border: 2px solid rgba(26, 42, 108, 0.2);
      border-radius: var(--border-radius);
      font-size: var(--font-size-md);
      background: var(--white);
      transition: var(--transition);
      color: var(--text);
      font-family: inherit;
    }

    input:focus,
    select:focus,
    textarea:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: var(--shadow-focus);
      transform: translateY(-2px);
    }

    /* FURPS: RELIABILITY - Input validation states */
    input:invalid,
    select:invalid {
      border-color: var(--danger);
      background-color: rgba(231, 57, 70, 0.05);
    }

    textarea:invalid {
      border-color: var(--danger);
      background-color: rgba(231, 57, 70, 0.05);
      border-radius: var(--border-radius);
    }

    input:valid,
    select:valid,
    textarea:valid {
      border-color: var(--success);
    }

    input[readonly],
    input:disabled {
      background-color: var(--gray);
      cursor: not-allowed;
      font-weight: 600;
      color: var(--secondary);
      opacity: 0.7;
    }

    /* FURPS: USABILITY - Radio & Checkbox groups */
    .checkbox-group, .radio-group {
      margin-top: var(--space-md);
      display: flex;
      flex-wrap: wrap;
      gap: var(--space-lg);
    }

    .checkbox-item, .radio-item {
      display: flex;
      align-items: center;
      cursor: pointer;
      padding: var(--space-sm) var(--space-md);
      border-radius: var(--border-radius);
      transition: var(--transition);
      background: rgba(255, 255, 255, 0.5);
      border: 1px solid rgba(0, 0, 0, 0.1);
      min-height: 44px; /* Minimum touch target */
    }

    .checkbox-item:hover, .radio-item:hover {
      background: rgba(255, 204, 0, 0.1);
      border-color: var(--primary);
    }

    .checkbox-item input, .radio-item input {
      margin-right: var(--space-sm);
      width: 18px;
      height: 18px;
      cursor: pointer;
      flex-shrink: 0;
    }

    .checkbox-item label, .radio-item label {
      margin: 0;
      cursor: pointer;
      font-weight: 500;
      font-size: var(--font-size-md);
    }

    /* FURPS: USABILITY - Custom radio and checkbox */
    input[type="radio"], input[type="checkbox"] {
      -webkit-appearance: none;
      appearance: none;
      width: 20px;
      height: 20px;
      border: 2px solid #ccc;
      border-radius: 4px;
      margin-right: var(--space-sm);
      position: relative;
      cursor: pointer;
      transition: var(--transition);
      flex-shrink: 0;
    }

    input[type="radio"] {
      border-radius: 50%;
    }

    input[type="radio"]:checked,
    input[type="checkbox"]:checked {
      background: var(--primary);
      border-color: var(--primary);
    }

    input[type="radio"]:checked::after {
      content: '';
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 10px;
      height: 10px;
      background: var(--secondary);
      border-radius: 50%;
    }

    input[type="checkbox"]:checked::after {
      content: '✓';
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      color: var(--secondary);
      font-weight: bold;
      font-size: 14px;
    }

    /* FURPS: USABILITY - Inline inputs */
    .inline-input {
      display: inline-flex;
      align-items: center;
      margin-left: var(--space-sm);
    }

    .inline-input input {
      width: 80px;
      margin-left: var(--space-sm);
      padding: var(--space-sm);
    }

    /* FURPS: USABILITY - Terms list */
    .terms-list {
      list-style: none;
      counter-reset: terms-counter;
      margin: var(--space-lg) 0;
    }

    .terms-list li {
      counter-increment: terms-counter;
      margin-bottom: var(--space-lg);
      padding-left: 40px;
      position: relative;
      line-height: 1.6;
    }

    .terms-list li::before {
      content: counter(terms-counter);
      position: absolute;
      left: 0;
      top: 0;
      background: var(--primary);
      color: var(--secondary);
      width: 28px;
      height: 28px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: var(--font-size-sm);
    }

    /* FURPS: FUNCTIONALITY - Price summary */
    .price-summary {
      background: linear-gradient(135deg, rgba(255, 204, 0, 0.1), rgba(26, 42, 108, 0.05));
      border-radius: 15px;
      padding: var(--space-lg);
      margin: var(--space-xl) 0;
      border: 2px solid rgba(255, 204, 0, 0.3);
    }

    .price-item {
      display: flex;
      justify-content: space-between;
      margin-bottom: var(--space-sm);
      padding-bottom: var(--space-sm);
      border-bottom: 1px dashed rgba(0, 0, 0, 0.1);
    }

    .price-item:last-child {
      border-bottom: none;
      font-weight: 700;
      font-size: var(--font-size-xl);
      color: var(--secondary);
      padding-top: var(--space-sm);
      margin-top: var(--space-sm);
      border-top: 2px solid var(--primary);
    }

    /* FURPS: USABILITY - Discount badge */
    .discount-badge {
      background: var(--success);
      color: white;
      padding: var(--space-xs) var(--space-md);
      border-radius: 20px;
      font-size: var(--font-size-xs);
      font-weight: 600;
      margin-left: var(--space-sm);
      animation: pulse 2s infinite;
    }

    @keyframes pulse {
      0% { transform: scale(1); }
      50% { transform: scale(1.05); }
      100% { transform: scale(1); }
    }

    /* FURPS: USABILITY - Buttons */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: var(--space-sm);
      background: var(--primary);
      color: var(--secondary);
      padding: var(--space-md) var(--space-xl);
      font-size: var(--font-size-lg);
      font-weight: 700;
      border: none;
      border-radius: 50px;
      cursor: pointer;
      transition: var(--transition);
      text-decoration: none;
      box-shadow: 0 5px 15px rgba(255, 204, 0, 0.3);
      margin-top: var(--space-xl);
      min-height: 44px;
      font-family: inherit;
    }

    .btn:hover,
    .btn:focus {
      background: #ffd633;
      transform: translateY(-5px);
      box-shadow: 0 10px 25px rgba(255, 204, 0, 0.4);
    }

    .btn:active {
      transform: translateY(-2px);
    }

    .btn i {
      font-size: var(--font-size-xl);
    }

    .btn-full {
      width: 100%;
      padding: var(--space-lg);
      font-size: var(--font-size-xl);
    }

    .btn-secondary {
      background: var(--secondary);
      color: var(--white);
      box-shadow: 0 5px 15px rgba(26, 42, 108, 0.3);
    }

    .btn-secondary:hover,
    .btn-secondary:focus {
      background: #2a3a9c;
      box-shadow: 0 10px 25px rgba(26, 42, 108, 0.4);
    }

    /* FURPS: FUNCTIONALITY - Signature section */
    .signature-section {
      display: flex;
      justify-content: space-between;
      margin-top: var(--space-xxl);
      padding-top: var(--space-lg);
      border-top: 2px solid rgba(0, 0, 0, 0.1);
    }

    .signature-box {
      flex: 1;
      margin: 0 var(--space-md);
    }

    /* FURPS: SUPPORTABILITY - Footer */
    .footer-note {
      font-size: var(--font-size-sm);
      color: var(--dark-gray);
      text-align: center;
      margin-top: var(--space-xxl);
      padding-top: var(--space-lg);
      border-top: 1px solid rgba(0, 0, 0, 0.1);
      line-height: 1.6;
    }

    /* FURPS: RELIABILITY - Alert system */
    .alert {
      padding: var(--space-md);
      border-radius: var(--border-radius);
      margin: var(--space-lg) 0;
      display: none;
      animation: fadeIn 0.3s ease;
      font-size: var(--font-size-md);
    }

    @keyframes fadeIn {
      from { opacity: 0; }
      to { opacity: 1; }
    }

    .alert-danger {
      background: rgba(231, 57, 70, 0.1);
      border: 2px solid var(--danger);
      color: var(--danger);
    }

    .alert-success {
      background: rgba(42, 157, 143, 0.1);
      border: 2px solid var(--success);
      color: var(--success);
    }

    .alert-warning {
      background: rgba(255, 152, 0, 0.1);
      border: 2px solid var(--warning);
      color: var(--warning);
    }

    .alert-info {
      background: rgba(26, 42, 108, 0.1);
      border: 2px solid var(--secondary);
      color: var(--secondary);
    }

    /* FURPS: USABILITY - Progress indicator */
    .progress-bar {
      width: 100%;
      height: 6px;
      background: rgba(0, 0, 0, 0.1);
      border-radius: 3px;
      margin: var(--space-xl) 0;
      overflow: hidden;
    }

    .progress {
      height: 100%;
      background: linear-gradient(to right, var(--primary), var(--secondary));
      border-radius: 3px;
      width: 0%;
      transition: width 0.5s ease;
    }

    /* FURPS: USABILITY - Price highlight */
    .price-highlight {
      background: linear-gradient(135deg, rgba(255, 204, 0, 0.2), rgba(26, 42, 108, 0.1));
      border-left: 4px solid var(--primary);
      padding: var(--space-md);
      border-radius: var(--border-radius);
      margin: var(--space-lg) 0;
    }

    .discount-info {
      background: rgba(42, 157, 143, 0.1);
      border: 2px dashed var(--success);
      border-radius: var(--border-radius);
      padding: var(--space-md);
      margin: var(--space-md) 0;
    }

    .discount-info h4 {
      color: var(--success);
      margin-bottom: var(--space-sm);
      display: flex;
      align-items: center;
      gap: var(--space-sm);
    }

    /* FURPS: FUNCTIONALITY - Final amount display */
    .final-amount {
      background: rgba(255, 204, 0, 0.15);
      border: 3px solid var(--primary);
      border-radius: 15px;
      padding: var(--space-lg);
      text-align: center;
      margin: var(--space-lg) 0;
    }

    .final-amount h3 {
      color: var(--secondary);
      margin-bottom: var(--space-sm);
      font-size: var(--font-size-xxl);
    }

    .final-amount .amount {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--secondary);
      margin: var(--space-sm) 0;
    }

    .final-amount .savings {
      color: var(--success);
      font-weight: 600;
      font-size: var(--font-size-lg);
    }

    /* FURPS: RELIABILITY - Equipment notice */
    .equipment-notice {
      background: rgba(168, 218, 220, 0.1);
      border: 2px dashed var(--light);
      border-radius: var(--border-radius);
      padding: var(--space-md);
      margin: var(--space-md) 0;
      font-size: var(--font-size-sm);
    }

    /* =========================================== */
    /* FURPS: USABILITY - Mobile Optimizations */
    /* =========================================== */
    @media (max-width: 768px) {
      body {
        padding: var(--space-sm);
      }

      .container {
        padding: var(--space-lg);
      }

      .checkbox-group, .radio-group {
        flex-direction: column;
        gap: var(--space-sm);
      }

      .checkbox-item, .radio-item {
        width: 100%;
      }

      .signature-section {
        flex-direction: column;
        gap: var(--space-lg);
      }

      .signature-box {
        margin: 0;
      }

      h1 {
        font-size: var(--font-size-xxl);
      }

      h2 {
        font-size: var(--font-size-lg);
      }
    }

    @media (max-width: 480px) {
      .container {
        padding: var(--space-md);
        border-radius: var(--border-radius);
      }

      .logo-text {
        font-size: var(--font-size-xxl);
      }

      .btn {
        padding: var(--space-md) var(--space-lg);
        font-size: var(--font-size-md);
      }

      .section-title {
        font-size: var(--font-size-xl);
      }

      .final-amount .amount {
        font-size: 1.8rem;
      }

      .logo-icon {
        animation: none;
      }
    }

    @media (max-width: 360px) {
      .container {
        padding: var(--space-sm);
      }

      h1 {
        font-size: var(--font-size-xl);
      }

      h2 {
        font-size: var(--font-size-md);
      }

      .final-amount .amount {
        font-size: 1.5rem;
      }

      .logo-text {
        font-size: var(--font-size-xl);
      }
    }

    /* FURPS: USABILITY - Landscape mode */
    @media (max-height: 500px) and (orientation: landscape) {
      body {
        padding: var(--space-xs);
      }

      .container {
        padding: var(--space-md);
        max-height: 90vh;
        overflow-y: auto;
      }

      .header {
        margin-bottom: var(--space-md);
      }

      .form-group {
        margin-bottom: var(--space-sm);
      }
    }

    /* =========================================== */
    /* FURPS: USABILITY - Accessibility Enhancements */
    /* =========================================== */
    /* Screen reader only text */
    .sr-only {
      position: absolute;
      width: 1px;
      height: 1px;
      padding: 0;
      margin: -1px;
      overflow: hidden;
      clip: rect(0, 0, 0, 0);
      white-space: nowrap;
      border: 0;
    }

    /* High contrast mode support */
    @media (prefers-contrast: high) {
      :root {
        --primary: #0000ff;
        --secondary: #000000;
        --danger: #ff0000;
        --success: #008000;
      }
      
      .btn {
        border: 2px solid black;
      }
      
      input, select, textarea {
        border: 2px solid black;
      }
    }

    /* Improve touch targets for mobile */
    @media (max-width: 480px) {
      input,
      select,
      button,
      .radio-item,
      .checkbox-item {
        min-height: 44px;
      }
      
      .btn {
        min-height: 48px;
      }
    }

    /* Prevent iOS zoom */
    @supports (-webkit-touch-callout: none) {
      input,
      select,
      textarea {
        font-size: 16px !important;
      }
    }

    /* FURPS: PERFORMANCE - Smooth scrolling */
    @media (prefers-reduced-motion: no-preference) {
      html {
        scroll-behavior: smooth;
      }
    }

    /* =========================================== */
    /* FURPS: RELIABILITY - Field hints & errors */
    /* =========================================== */
    .field-hint {
      display: block;
      margin-top: var(--space-xs);
      color: var(--dark-gray);
      font-size: var(--font-size-sm);
    }

    .field-error {
      color: var(--danger);
      font-size: var(--font-size-sm);
      margin-top: var(--space-xs);
      display: none;
      font-weight: 500;
    }

    input:invalid + .field-error,
    select:invalid + .field-error,
    textarea:invalid + .field-error {
      display: block;
    }

    /* FURPS: RELIABILITY - Loading states */
    .loading {
      opacity: 0.7;
      pointer-events: none;
    }

    .loading::after {
      content: '';
      display: inline-block;
      width: 16px;
      height: 16px;
      margin-left: 8px;
      border: 2px solid var(--white);
      border-top-color: transparent;
      border-radius: 50%;
      animation: spin 1s linear infinite;
    }

    @keyframes spin {
      to { transform: rotate(360deg); }
    }

    /* FURPS: USABILITY - Tooltips */
    [data-tooltip] {
      position: relative;
    }

    [data-tooltip]::before {
      content: attr(data-tooltip);
      position: absolute;
      bottom: 100%;
      left: 50%;
      transform: translateX(-50%);
      background: var(--secondary);
      color: var(--white);
      padding: var(--space-xs) var(--space-sm);
      border-radius: var(--border-radius);
      font-size: var(--font-size-xs);
      white-space: nowrap;
      opacity: 0;
      visibility: hidden;
      transition: opacity 0.3s, visibility 0.3s;
      z-index: var(--z-tooltip);
    }

    [data-tooltip]:hover::before,
    [data-tooltip]:focus::before {
      opacity: 1;
      visibility: visible;
    }

    /* =========================================== */
    /* FURPS: FUNCTIONALITY - Offline indicator */
    /* =========================================== */
    .offline-indicator {
      position: fixed;
      top: 20px;
      right: 20px;
      background: var(--danger);
      color: white;
      padding: var(--space-sm) var(--space-md);
      border-radius: var(--border-radius);
      z-index: var(--z-modal);
      display: none;
      animation: slideInRight 0.3s ease;
      box-shadow: var(--shadow);
    }

    @keyframes slideInRight {
      from {
        transform: translateX(100%);
        opacity: 0;
      }
      to {
        transform: translateX(0);
        opacity: 1;
      }
    }

    /* =========================================== */
    /* FURPS: PERFORMANCE - Print styles */
    /* =========================================== */
    @media print {
      body {
        background: white !important;
        color: black !important;
      }
      
      .container {
        box-shadow: none !important;
        border: 1px solid #ccc !important;
        background: white !important;
      }
      
      .btn,
      .progress-bar,
      .alert,
      .footer-note {
        display: none !important;
      }
      
      .final-amount {
        break-inside: avoid;
      }
    }

    /* FURPS: PERFORMANCE - Optimize animations */
    @media (prefers-reduced-motion: reduce) {
      .logo-icon {
        animation: none;
      }
      
      .discount-badge {
        animation: none;
      }
      
      .container {
        animation: none;
      }
    }