:root {
  --bg-primary: #202940;
  --bg-secondary: #161D2D;
  --accent: #CCFF00;
  --accent-hover: #E2FF4D;
  --text-main: #FFFFFF;
  --text-muted: #8B9BB4;
  --border-color: #384666;
  
  --font-mono: 'Space Mono', monospace;
  --font-sans: 'Outfit', sans-serif;
  
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  height: 100dvh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

/* Screen Reader Only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.app-container {
  width: 100%;
  max-width: 480px;
  height: 100dvh;
  max-height: 100dvh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
  border-left: 2px solid var(--border-color);
  border-right: 2px solid var(--border-color);
  box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
}

@media (min-width: 481px) {
  .app-container {
    height: 90vh;
    border: 4px solid var(--border-color);
    border-radius: 8px;
  }
}

/* Header / Total */
.total-display {
  background-color: var(--bg-secondary);
  padding: var(--spacing-lg) var(--spacing-md);
  border-bottom: 4px solid var(--accent);
  text-align: right;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  position: relative;
  overflow: hidden;
}

.total-display::before {
  content: "SYS.CALC.01";
  position: absolute;
  top: var(--spacing-md);
  left: var(--spacing-md);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
}

.total-label {
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  margin-bottom: var(--spacing-sm);
}

.total-value {
  font-family: var(--font-mono);
  font-size: 3.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--accent);
  text-shadow: 0 0 20px rgba(204, 255, 0, 0.2);
}

/* Receipt Area */
.receipt-area {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-md);
  background-image: linear-gradient(var(--bg-primary) 50%, var(--bg-secondary) 50%);
  background-size: 100% 4px;
}

.receipt-header {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  border-bottom: 1px dashed var(--border-color);
  padding-bottom: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.receipt-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.receipt-item {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 1.25rem;
  padding: var(--spacing-sm) 0;
  animation: slideIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
  opacity: 0;
  transform: translateY(20px);
}

.item-index {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-right: var(--spacing-sm);
}

.item-price {
  font-weight: 700;
}

/* Input Area */
.input-area {
  background-color: var(--bg-secondary);
  padding: var(--spacing-md);
  padding-bottom: calc(var(--spacing-md) + env(safe-area-inset-bottom, 20px));
  border-top: 2px solid var(--border-color);
}

#addForm {
  display: flex;
  gap: var(--spacing-md);
}

.input-wrapper {
  flex: 1;
  display: flex;
  align-items: center;
  background-color: var(--bg-primary);
  border: 2px solid var(--border-color);
  padding: 0 var(--spacing-md);
  transition: border-color 0.2s ease;
}

.input-wrapper:focus-within {
  border-color: var(--accent);
}

.currency-symbol {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  color: var(--text-muted);
}

input[type="number"] {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  padding: var(--spacing-sm);
  outline: none;
  width: 100%;
}

input[type="number"]::placeholder {
  color: var(--text-muted);
  opacity: 0.3;
}

/* Hide spin buttons */
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
input[type="number"] {
  -moz-appearance: textfield;
}

.btn-add {
  background-color: var(--accent);
  color: var(--bg-primary);
  border: none;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: 1rem;
  line-height: 1.1;
  padding: 0 var(--spacing-lg);
  cursor: pointer;
  text-transform: uppercase;
  transition: all 0.2s ease;
}

.btn-add:hover {
  background-color: var(--accent-hover);
  transform: scale(1.02);
}

.btn-add:active {
  transform: scale(0.98);
}

/* Animations */
@keyframes slideIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* Reset Button */
.btn-reset {
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.5rem;
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.2s ease;
}

.btn-reset:hover {
  background: var(--border-color);
  color: var(--text-main);
}

.btn-reset:active {
  transform: scale(0.95);
}

/* Item Actions & Delete Button */
.item-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.btn-delete-item {
  background: transparent;
  border: 1px solid transparent;
  color: #ff4d4d;
  font-size: 1.5rem;
  line-height: 1;
  width: 24px;
  height: 24px;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.2s ease;
  opacity: 0.5;
}

.btn-delete-item:hover {
  background: rgba(255, 77, 77, 0.1);
  border-color: #ff4d4d;
  opacity: 1;
}

.btn-delete-item:active {
  transform: scale(0.9);
}

/* Custom Modal */
.modal-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 100;
  backdrop-filter: blur(4px);
  opacity: 1;
  transition: opacity 0.2s ease;
}

.modal-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.modal-content {
  background: var(--bg-primary);
  border: 2px solid var(--accent);
  padding: var(--spacing-lg);
  max-width: 90%;
  text-align: center;
  box-shadow: 0 0 30px rgba(204, 255, 0, 0.1);
}

.modal-content p {
  margin-bottom: var(--spacing-lg);
  font-weight: 700;
  font-size: 1.1rem;
}

.modal-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
}

.btn-modal {
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-sans);
  font-weight: 900;
  cursor: pointer;
  border: none;
  text-transform: uppercase;
  transition: transform 0.1s ease;
}

.btn-cancel {
  background: var(--bg-secondary);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-confirm {
  background: #ff4d4d;
  color: #fff;
}

.btn-modal:hover {
  transform: scale(1.05);
}

.btn-modal:active {
  transform: scale(0.95);
}