:root {
  /* Color Palette - Neutral base with subtle accents */
  --bg-primary: #0f1115;
  --bg-secondary: #1a1d24;
  --bg-tertiary: #252a33;
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border-color: #334155;
  --border-hover: #475569;
  
  /* Fuel Accent Colors */
  --accent-petrol: #0ea5e9;    /* Clean blue */
  --accent-diesel: #f59e0b;    /* Clean amber */
  --accent-xfuel: #ec4899;     /* Clean pink */
  
  --accent-current: var(--accent-petrol); /* Dynamic based on selection */
  
  /* Status Colors */
  --color-success: #10b981;
  --color-error: #ef4444;
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Roboto Mono', 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  
  /* Spacing */
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-3: 0.75rem;
  --spacing-4: 1rem;
  --spacing-6: 1.5rem;
  --spacing-8: 2rem;
  --spacing-12: 3rem;
  
  /* Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-primary);
  font-weight: 600;
  line-height: 1.2;
}

h1 { font-size: 2rem; margin-bottom: var(--spacing-6); }
h2 { font-size: 1.5rem; margin-bottom: var(--spacing-4); }

p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-4);
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

.header {
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-primary);
  padding: var(--spacing-4) 0;
  position: sticky;
  top: 0;
  z-index: 10;
}

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

.logo-container {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
}

.logo-icon {
  color: var(--accent-current);
  font-size: 1.5rem;
  transition: color 0.3s ease;
}

.main-content {
  flex: 1;
  padding: var(--spacing-12) 0;
}

/* Dashboard Layout */
.dashboard {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-8);
}

@media (min-width: 992px) {
  .dashboard {
    grid-template-columns: 350px 1fr;
  }
}

/* Panels */
.panel {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--spacing-6);
  box-shadow: var(--shadow-md);
}

.panel-title {
  font-size: 1.125rem;
  margin-bottom: var(--spacing-6);
  padding-bottom: var(--spacing-4);
  border-bottom: 1px solid var(--border-color);
  color: var(--text-primary);
}

/* Form Elements */
.form-group {
  margin-bottom: var(--spacing-6);
}

.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-2);
}

.form-control {
  width: 100%;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: var(--spacing-3) var(--spacing-4);
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: 1rem;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus {
  outline: none;
  border-color: var(--accent-current);
  box-shadow: 0 0 0 2px rgba(14, 165, 233, 0.2); /* Fallback color, normally would use rgb version of accent */
}

/* Custom for specific inputs based on fuel type */
body[data-fuel="petrol"] .form-control:focus { border-color: var(--accent-petrol); box-shadow: 0 0 0 2px rgba(14, 165, 233, 0.2); }
body[data-fuel="diesel"] .form-control:focus { border-color: var(--accent-diesel); box-shadow: 0 0 0 2px rgba(245, 158, 11, 0.2); }
body[data-fuel="xfuel"] .form-control:focus  { border-color: var(--accent-xfuel); box-shadow: 0 0 0 2px rgba(236, 72, 153, 0.2); }


/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-4);
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s;
  border: 1px solid transparent;
  font-family: var(--font-sans);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background-color: var(--accent-current);
  color: white;
}

.btn-primary:hover:not(:disabled) {
  filter: brightness(1.1);
}

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-color);
}

.btn-secondary:hover:not(:disabled) {
  background-color: var(--border-color);
}

.btn-danger {
  background-color: var(--color-error);
  color: white;
}

.btn-danger:hover:not(:disabled) {
  filter: brightness(1.1);
}

.btn-group {
  display: flex;
  gap: var(--spacing-3);
  margin-top: var(--spacing-6);
}

.btn-group .btn {
  flex: 1;
}

/* Fuel Selector */
.fuel-selector {
  display: flex;
  gap: var(--spacing-2);
  background-color: var(--bg-tertiary);
  padding: var(--spacing-1);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.fuel-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: var(--spacing-2) 0;
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s;
}

.fuel-btn:hover:not(.active) {
  color: var(--text-primary);
  background-color: rgba(255, 255, 255, 0.05);
}

.fuel-btn[data-type="petrol"].active {
  background-color: var(--accent-petrol);
  color: white;
  box-shadow: var(--shadow-sm);
}

.fuel-btn[data-type="diesel"].active {
  background-color: var(--accent-diesel);
  color: white;
  box-shadow: var(--shadow-sm);
}

.fuel-btn[data-type="xfuel"].active {
  background-color: var(--accent-xfuel);
  color: white;
  box-shadow: var(--shadow-sm);
}

/* Digital Displays */
.displays-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-4);
  margin-bottom: var(--spacing-6);
}

.display-card {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-4);
  display: flex;
  flex-direction: column;
}

.display-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-2);
}

.display-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--text-primary);
  margin-top: auto;
}

/* Emphasized Total Display */
.display-card.total-card {
  background-color: rgba(14, 165, 233, 0.1);
  border-color: rgba(14, 165, 233, 0.3);
}
body[data-fuel="diesel"] .display-card.total-card {
  background-color: rgba(245, 158, 11, 0.1);
  border-color: rgba(245, 158, 11, 0.3);
}
body[data-fuel="xfuel"] .display-card.total-card {
  background-color: rgba(236, 72, 153, 0.1);
  border-color: rgba(236, 72, 153, 0.3);
}

.total-card .display-value {
  font-size: 2.25rem;
  color: var(--accent-current);
}

/* Footer & Support Section */
.footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  padding: var(--spacing-4) 0;
  margin-top: auto;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-3);
  text-align: center;
}

.footer-links {
  display: flex;
  gap: var(--spacing-4);
  flex-wrap: wrap;
  justify-content: center;
}

.minimal-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-2);
  transition: color 0.2s;
  cursor: pointer;
}

.minimal-link:hover {
  color: var(--text-primary);
}

.crypto-link span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.footer-text {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Utilities */
.text-center { text-align: center; }
.mb-4 { margin-bottom: var(--spacing-4); }
.mt-4 { margin-top: var(--spacing-4); }

/* Receipt Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: var(--spacing-4);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, visibility 0.2s;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  width: 100%;
  max-width: 400px;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-overlay.active .modal {
  transform: translateY(0);
}

.modal-header {
  padding: var(--spacing-4) var(--spacing-6);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
}

.modal-close {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: var(--spacing-1);
  font-size: 1.25rem;
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-6);
}

/* Receipt Styling */
.receipt {
  background-color: var(--bg-primary);
  border: 1px dashed var(--border-color);
  padding: var(--spacing-4);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  margin-bottom: var(--spacing-6);
}

.receipt-header {
  text-align: center;
  margin-bottom: var(--spacing-4);
  padding-bottom: var(--spacing-4);
  border-bottom: 1px dashed var(--border-color);
}

.receipt-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--spacing-2);
}

.receipt-total {
  margin-top: var(--spacing-4);
  padding-top: var(--spacing-4);
  border-top: 1px dashed var(--border-color);
  font-weight: 700;
  font-size: 1rem;
}

/* Print styles */
@media print {
  body * {
    visibility: hidden;
  }
  #receiptModal, #receiptModal * {
    visibility: visible;
  }
  #receiptModal {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    transform: none;
    background: white;
    color: black;
    box-shadow: none;
    border: none;
  }
  .modal-close, .btn-group {
    display: none !important;
  }
  .receipt {
    border-color: black;
    background: white;
    color: black;
  }
}