:root {
  /* Enhanced Color System */
  --drev-primary: #1a73e8;
  --drev-primary-dark: #0d62d9;
  --drev-primary-2: #4f46e5;
  --drev-primary-2-dark: #4338ca;
  --drev-gradient: linear-gradient(135deg, var(--drev-primary), var(--drev-primary-2));
  --drev-gradient-hover: linear-gradient(135deg, var(--drev-primary-dark), var(--drev-primary-2-dark));
  
  /* Modern Surface Colors */
  --drev-surface-1: #ffffff;
  --drev-surface-2: #f8fafc;
  --drev-surface-3: #f1f5f9;
  --drev-surface-glass: rgba(255, 255, 255, 0.85);
  
  /* Text Colors */
  --drev-text-primary: #0f172a;
  --drev-text-secondary: #475569;
  --drev-text-tertiary: #64748b;
  
  /* Border & Shadow System */
  --drev-border-light: rgba(226, 232, 240, 0.6);
  --drev-border: #e2e8f0;
  --drev-border-dark: #cbd5e1;
  
  --drev-shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --drev-shadow: 0 4px 6px -1px rgba(15, 23, 42, 0.1), 0 2px 4px -1px rgba(15, 23, 42, 0.06);
  --drev-shadow-lg: 0 10px 25px -5px rgba(15, 23, 42, 0.15), 0 8px 10px -6px rgba(15, 23, 42, 0.1);
  --drev-shadow-xl: 0 25px 50px -12px rgba(15, 23, 42, 0.25);
  --drev-shadow-glow: 0 0 40px rgba(79, 70, 229, 0.15);
  
  /* Spacing Scale */
  --drev-space-xs: 4px;
  --drev-space-sm: 8px;
  --drev-space-md: 16px;
  --drev-space-lg: 24px;
  --drev-space-xl: 32px;
  
  /* Typography */
  --drev-font-heading: 'Inter', 'Manrope', 'Segoe UI', sans-serif;
  --drev-font-body: 'Manrope', 'Segoe UI', sans-serif;
  --drev-font-mono: 'JetBrains Mono', 'SF Mono', monospace;
  
  /* Animation Timing */
  --drev-transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --drev-transition: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --drev-transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
  
  /* Border Radius */
  --drev-radius-sm: 8px;
  --drev-radius: 12px;
  --drev-radius-lg: 16px;
  --drev-radius-xl: 20px;
  --drev-radius-full: 999px;
  
  /* Glass Effects */
  --drev-glass-bg: rgba(255, 255, 255, 0.7);
  --drev-glass-border: rgba(255, 255, 255, 0.2);
  --drev-glass-shadow: 0 8px 32px rgba(31, 38, 135, 0.1);
  
  /* Accent Colors */
  --drev-success: #10b981;
  --drev-warning: #f59e0b;
  --drev-error: #ef4444;
  --drev-info: #3b82f6;
}

/* Enhanced Body Lock */
body.drevcheckout-locked {
  overflow: hidden;
  padding-right: var(--scrollbar-width, 0px);
}

.drevcheckout-scrollbar-compensation {
  margin-right: var(--scrollbar-width, 0px);
}

/* Advanced Overlay with Parallax Effect */
.drevcheckout-overlay {
  position: fixed;
  inset: 0;
  background: linear-gradient(135deg, 
    rgba(15, 23, 42, 0.95) 0%,
    rgba(30, 41, 59, 0.92) 100%
  );
  backdrop-filter: blur(10px) saturate(180%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--drev-space-md);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--drev-transition-slow);
  z-index: 999999;
}

.drevcheckout-overlay::before {
  content: '';
  position: absolute;
  inset: 0;
  background: 
    radial-gradient(circle at 20% 80%, rgba(79, 70, 229, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(14, 165, 233, 0.1) 0%, transparent 50%);
  animation: drev-particle-float 20s ease-in-out infinite;
}

.drevcheckout-overlay.is-visible {
  opacity: 1;
  pointer-events: auto;
}

@keyframes drev-particle-float {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  33% { transform: translate(30px, -30px) rotate(120deg); }
  66% { transform: translate(-20px, 20px) rotate(240deg); }
}

/* Futuristic Modal */
.drevcheckout-modal {
  width: min(800px, 95vw);
  max-height: min(90vh, 800px);
  perspective: 1000px;
}

.drevcheckout-frame {
  background: var(--drev-surface-glass);
  border-radius: var(--drev-radius-xl);
  border: 1px solid var(--drev-glass-border);
  backdrop-filter: blur(20px);
  box-shadow: 
    var(--drev-shadow-xl),
    var(--drev-shadow-glow),
    inset 0 1px 0 rgba(255, 255, 255, 0.4),
    inset 0 -1px 0 rgba(0, 0, 0, 0.05);
  transform: 
    scale(0.8) 
    translateY(40px) 
    rotateX(-10deg);
  opacity: 0;
  transition: 
    transform var(--drev-transition-slow),
    opacity var(--drev-transition-slow);
  overflow: hidden;
  position: relative;
}

.drevcheckout-frame::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    transparent 0%,
    rgba(255, 255, 255, 0.1) 50%,
    transparent 100%
  );
  animation: drev-shine 3s ease-in-out infinite;
  pointer-events: none;
}

.drevcheckout-frame.is-visible {
  transform: scale(1) translateY(0) rotateX(0);
  opacity: 1;
}

@keyframes drev-shine {
  0%, 100% { transform: translateX(-100%); }
  50% { transform: translateX(100%); }
}

/* Enhanced Loader with Morphing Shapes */
.drevcheckout-loader {
  position: absolute;
  inset: 0;
  background: var(--drev-surface-glass);
  backdrop-filter: blur(10px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--drev-space-md);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--drev-transition);
  z-index: 10;
}

.drevcheckout-loader.is-active {
  opacity: 1;
  pointer-events: auto;
}

.drevcheckout-spinner {
  width: 60px;
  height: 60px;
  position: relative;
}

.drevcheckout-spinner::before,
.drevcheckout-spinner::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 50%;
  animation: drev-morph 2s ease-in-out infinite;
}

.drevcheckout-spinner::before {
  background: var(--drev-gradient);
  animation-delay: -1s;
}

.drevcheckout-spinner::after {
  background: var(--drev-primary-2);
  animation-delay: 0s;
}

@keyframes drev-morph {
  0%, 100% {
    border-radius: 50%;
    transform: scale(1) rotate(0deg);
  }
  33% {
    border-radius: 40% 60% 60% 40% / 60% 40% 60% 40%;
    transform: scale(1.1) rotate(120deg);
  }
  66% {
    border-radius: 60% 40% 40% 60% / 40% 60% 40% 60%;
    transform: scale(0.9) rotate(240deg);
  }
}

.drevcheckout-loader-text {
  font-family: var(--drev-font-heading);
  font-weight: 600;
  color: var(--drev-text-primary);
  font-size: 0.95rem;
  position: relative;
}

.drevcheckout-loader-text::after {
  content: '...';
  animation: drev-dots 1.5s steps(4, end) infinite;
}

@keyframes drev-dots {
  0%, 20% { content: ''; }
  40% { content: '.'; }
  60% { content: '..'; }
  80%, 100% { content: '...'; }
}

/* Cyberpunk Header */
.drevcheckout-header {
  background: linear-gradient(135deg,
    #0f172a 0%,
    #1e293b 50%,
    #334155 100%
  );
  padding: var(--drev-space-lg) var(--drev-space-xl);
  position: relative;
  overflow: hidden;
}

.drevcheckout-header::before {
  content: '';
  position: absolute;
  inset: 0;
  background: 
    linear-gradient(90deg, transparent 0%, rgba(79, 70, 229, 0.1) 50%, transparent 100%),
    repeating-linear-gradient(
      45deg,
      transparent,
      transparent 2px,
      rgba(79, 70, 229, 0.05) 2px,
      rgba(79, 70, 229, 0.05) 4px
    );
  animation: drev-scan 20s linear infinite;
}

.drevcheckout-header::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    rgba(79, 70, 229, 0.6),
    rgba(14, 165, 233, 0.6),
    transparent
  );
  animation: drev-scanline 3s linear infinite;
}

@keyframes drev-scan {
  0% { background-position: -100% 0; }
  100% { background-position: 200% 0; }
}

@keyframes drev-scanline {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.drevcheckout-title {
  font-family: var(--drev-font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  color: white;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  position: relative;
  z-index: 1;
}

.drevcheckout-close {
  width: 40px;
  height: 40px;
  border-radius: var(--drev-radius-full);
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: white;
  cursor: pointer;
  transition: all var(--drev-transition-fast);
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.drevcheckout-close::before {
  content: '×';
  font-size: 24px;
  line-height: 1;
}

.drevcheckout-close:hover {
  background: rgba(255, 255, 255, 0.2);
  transform: rotate(90deg) scale(1.1);
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

/* Modern Grid Layout with Card Hover Effects */
.drevcheckout-columns {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: var(--drev-space-lg);
  padding: var(--drev-space-lg);
}

.drevcheckout-col {
  background: var(--drev-surface-glass);
  border: 1px solid var(--drev-border-light);
  border-radius: var(--drev-radius-lg);
  padding: var(--drev-space-xl);
  backdrop-filter: blur(10px);
  transition: all var(--drev-transition);
  position: relative;
  overflow: hidden;
}

.drevcheckout-col::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg,
    rgba(26, 115, 232, 0.05) 0%,
    rgba(79, 70, 229, 0.05) 100%
  );
  opacity: 0;
  transition: opacity var(--drev-transition);
  pointer-events: none;
}

.drevcheckout-col:hover {
  transform: translateY(-2px);
  box-shadow: var(--drev-shadow-lg);
  border-color: var(--drev-primary);
}

.drevcheckout-col:hover::before {
  opacity: 1;
}

/* Advanced Form Elements */
.drevcheckout-form .form-row {
  position: relative;
  margin-bottom: var(--drev-space-md);
}

.drevcheckout-form .form-row label {
  display: block;
  font-family: var(--drev-font-heading);
  font-weight: 600;
  color: var(--drev-text-primary);
  margin-bottom: var(--drev-space-xs);
  font-size: 0.875rem;
  transition: color var(--drev-transition-fast);
}

.drevcheckout-form .form-row input,
.drevcheckout-form .form-row textarea,
.drevcheckout-form .form-row select {
  width: 100%;
  padding: 12px 16px;
  font-family: var(--drev-font-body);
  font-size: 0.9375rem;
  background: var(--drev-surface-2);
  border: 2px solid var(--drev-border);
  border-radius: var(--drev-radius);
  color: var(--drev-text-primary);
  transition: all var(--drev-transition-fast);
}

.drevcheckout-form .form-row input:focus,
.drevcheckout-form .form-row textarea:focus,
.drevcheckout-form .form-row select:focus {
  outline: none;
  border-color: var(--drev-primary);
  background: var(--drev-surface-1);
  box-shadow: 
    0 0 0 4px rgba(26, 115, 232, 0.1),
    inset 0 0 0 1px rgba(255, 255, 255, 0.8);
}

.drevcheckout-form .form-row input:not(:placeholder-shown):valid {
  border-color: var(--drev-success);
  background: linear-gradient(to right, 
    var(--drev-surface-2) calc(100% - 40px),
    rgba(16, 185, 129, 0.1) calc(100% - 40px)
  );
}

.drevcheckout-form .form-row input:not(:placeholder-shown):invalid {
  border-color: var(--drev-error);
}

/* Floating Labels (Optional Enhancement) */
.drevcheckout-form .form-row.floating-label {
  margin-top: 24px;
}

.drevcheckout-form .form-row.floating-label label {
  position: absolute;
  top: 14px;
  left: 16px;
  background: var(--drev-surface-2);
  padding: 0 8px;
  transition: all var(--drev-transition-fast);
  pointer-events: none;
}

.drevcheckout-form .form-row.floating-label input:focus + label,
.drevcheckout-form .form-row.floating-label input:not(:placeholder-shown) + label {
  top: -8px;
  font-size: 0.75rem;
  color: var(--drev-primary);
  background: var(--drev-surface-1);
}

/* Modern Checkbox & Radio */
.drevcheckout-form input[type="checkbox"],
.drevcheckout-form input[type="radio"] {
  width: 18px;
  height: 18px;
  margin-right: 8px;
  vertical-align: middle;
  cursor: pointer;
}

.drevcheckout-form input[type="checkbox"] {
  border-radius: 4px;
}

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

/* Enhanced CTA Block with Neon Effect */
.drevcheckout-cta-block {
  background: linear-gradient(135deg,
    var(--drev-primary) 0%,
    var(--drev-primary-2) 100%
  );
  border-radius: var(--drev-radius-lg);
  padding: var(--drev-space-xl);
  color: white;
  position: relative;
  overflow: hidden;
}

.drevcheckout-cta-block::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(45deg,
    transparent 30%,
    rgba(255, 255, 255, 0.1) 50%,
    transparent 70%
  );
  animation: drev-neon 3s ease-in-out infinite;
}

@keyframes drev-neon {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.6; }
}

.drevcheckout-cta-text {
  font-family: var(--drev-font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--drev-space-md);
  position: relative;
  z-index: 1;
}

/* Futuristic Submit Button */
.drevcheckout-submit {
  width: 100%;
  padding: 16px 24px;
  font-family: var(--drev-font-heading);
  font-size: 1rem;
  font-weight: 700;
  background: linear-gradient(135deg,
    #111827 0%,
    #1f2937 100%
  );
  color: white;
  border: none;
  border-radius: var(--drev-radius);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: all var(--drev-transition);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.drevcheckout-submit::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(255, 255, 255, 0.1) 50%,
    transparent 100%
  );
  transform: translateX(-100%);
}

.drevcheckout-submit:hover {
  transform: translateY(-2px);
  box-shadow: 
    0 12px 30px -10px rgba(15, 23, 42, 0.5),
    0 0 30px rgba(79, 70, 229, 0.4);
}

.drevcheckout-submit:hover::before {
  animation: drev-shimmer 1s ease-out;
}

@keyframes drev-shimmer {
  to { transform: translateX(100%); }
}

.drevcheckout-submit.is-loading {
  opacity: 0.9;
  cursor: not-allowed;
}

.drevcheckout-submit-progress {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  animation: drev-spin 0.8s linear infinite;
}

/* Enhanced Mini Cart */
.drevcheckout-mini-cart {
  background: var(--drev-surface-glass);
  border: 1px solid var(--drev-border-light);
  border-radius: var(--drev-radius-lg);
  padding: var(--drev-space-lg);
  position: relative;
  backdrop-filter: blur(10px);
}

.drevcheckout-mini-cart::before {
  content: '🛒 Order Summary';
  position: absolute;
  top: -12px;
  left: 20px;
  background: linear-gradient(135deg, var(--drev-primary), var(--drev-primary-2));
  color: white;
  padding: 4px 16px;
  border-radius: var(--drev-radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  box-shadow: var(--drev-shadow);
  z-index: 1;
}

.drevcheckout-mini-cart::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    var(--drev-primary),
    transparent
  );
}

/* Advanced Notices with Slide-in Animation */
.drevcheckout-notices {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 1000;
  width: min(400px, 90vw);
}

.drevcheckout-notices .woocommerce-message,
.drevcheckout-notices .woocommerce-info,
.drevcheckout-notices .woocommerce-error {
  margin-bottom: 12px;
  padding: 16px 20px;
  border-radius: var(--drev-radius);
  border-left: 4px solid;
  background: white;
  box-shadow: var(--drev-shadow-lg);
  animation: drev-slide-in-right 0.3s ease-out;
  transform-origin: right center;
}

.drevcheckout-notices .woocommerce-message {
  border-left-color: var(--drev-success);
  background: linear-gradient(to right, white, rgba(16, 185, 129, 0.05));
}

.drevcheckout-notices .woocommerce-info {
  border-left-color: var(--drev-info);
  background: linear-gradient(to right, white, rgba(59, 130, 246, 0.05));
}

.drevcheckout-notices .woocommerce-error {
  border-left-color: var(--drev-error);
  background: linear-gradient(to right, white, rgba(239, 68, 68, 0.05));
}

@keyframes drev-slide-in-right {
  from {
    opacity: 0;
    transform: translateX(30px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateX(0) scale(1);
  }
}

/* Progress Indicator */
.drevcheckout-progress {
  display: flex;
  justify-content: space-between;
  position: relative;
  margin: var(--drev-space-xl) 0;
  padding: 0 var(--drev-space-md);
}

.drevcheckout-progress::before {
  content: '';
  position: absolute;
  top: 50%;
  left: var(--drev-space-md);
  right: var(--drev-space-md);
  height: 2px;
  background: var(--drev-border);
  transform: translateY(-50%);
  z-index: 0;
}

.drevcheckout-progress-step {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: white;
  border: 2px solid var(--drev-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  color: var(--drev-text-secondary);
  position: relative;
  z-index: 1;
  transition: all var(--drev-transition);
}

.drevcheckout-progress-step.active {
  background: var(--drev-primary);
  border-color: var(--drev-primary);
  color: white;
  transform: scale(1.1);
  box-shadow: 0 0 0 4px rgba(26, 115, 232, 0.2);
}

/* Responsive Design Enhancements */
@media (max-width: 1024px) {
  .drevcheckout-columns {
    grid-template-columns: 1fr;
    gap: var(--drev-space-md);
  }
  
  .drevcheckout-col {
    padding: var(--drev-space-lg);
  }
}

@media (max-width: 768px) {
  :root {
    --drev-popup-width: 95vw;
  }
  
  .drevcheckout-modal {
    width: 95vw;
    max-height: 95vh;
  }
  
  .drevcheckout-header {
    padding: var(--drev-space-md);
  }
  
  .drevcheckout-columns {
    padding: var(--drev-space-md);
  }
  
  .drevcheckout-form .woocommerce-billing-fields__field-wrapper {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .drevcheckout-col {
    padding: var(--drev-space-md);
  }
  
  .drevcheckout-title {
    font-size: 1.2rem;
  }
  
  .drevcheckout-submit {
    padding: 14px 20px;
  }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
  :root {
    --drev-surface-1: #1e293b;
    --drev-surface-2: #0f172a;
    --drev-surface-3: #334155;
    --drev-text-primary: #f1f5f9;
    --drev-text-secondary: #cbd5e1;
    --drev-text-tertiary: #94a3b8;
    --drev-border: #475569;
    --drev-border-light: rgba(71, 85, 105, 0.5);
  }
  
  .drevcheckout-frame {
    background: rgba(30, 41, 59, 0.9);
    border-color: rgba(71, 85, 105, 0.3);
  }
  
  .drevcheckout-col {
    background: rgba(30, 41, 59, 0.7);
  }
}

/* Accessibility Improvements */
.drevcheckout-close:focus-visible,
.drevcheckout-submit:focus-visible,
.drevcheckout-form input:focus-visible {
  outline: 2px solid var(--drev-primary);
  outline-offset: 2px;
}

/* Print Styles */
@media print {
  .drevcheckout-overlay {
    position: static;
    background: white;
  }
  
  .drevcheckout-frame {
    box-shadow: none;
    border: 1px solid #ddd;
  }
  
  .drevcheckout-close,
  .drevcheckout-loader {
    display: none !important;
  }
}