:root {
  /* Color World - Fintech/Trustworthy */
  --bg-canvas: #f8fafc;        /* Off-white background */
  --bg-surface: #ffffff;       /* Card/Panel background */
  --text-primary: #1e293b;     /* Charcoal for main text */
  --text-secondary: #64748b;   /* Muted text for labels/hints */
  --border-subtle: #e2e8f0;    /* Soft borders */
  
  /* Actions & Semantics */
  --action-primary: #4f46e5;   /* Indigo/Blue */
  --action-hover: #4338ca;
  --status-success: #10b981;   /* Subtle green */
  --status-success-bg: #d1fae5;
  --status-error: #ef4444;     /* Subtle red */
  --status-error-bg: #fee2e2;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  
  /* Elevation & Effects */
  --shadow-subtle: 0 1px 3px 0 rgba(0, 0, 0, 0.05), 0 1px 2px 0 rgba(0, 0, 0, 0.03);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --focus-ring: 0 0 0 3px rgba(79, 70, 229, 0.2);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

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

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

/* Layout */
.layout-centered {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  padding: var(--space-4);
}

.layout-dashboard {
  padding: var(--space-6);
  max-width: 800px;
  margin: 0 auto;
  width: 100%;
}

.card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-subtle);
  padding: var(--space-6);
  width: 100%;
  max-width: 440px;
}

.card-dashboard {
  max-width: none;
  margin-bottom: var(--space-6);
}

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

h1 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-6);
  text-align: center;
}

.title-left {
  text-align: left;
  font-size: var(--text-xl);
  margin-bottom: var(--space-4);
}

p {
  color: var(--text-secondary);
}

/* Forms */
.form-group {
  margin-bottom: var(--space-4);
}

label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.form-input {
  width: 100%;
  padding: var(--space-3);
  font-size: var(--text-base);
  font-family: var(--font-family);
  color: var(--text-primary);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
}

.form-input:focus {
  outline: none;
  border-color: var(--action-primary);
  box-shadow: var(--focus-ring);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: var(--space-3);
  font-size: var(--text-base);
  font-weight: 600;
  font-family: var(--font-family);
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background-color: var(--action-primary);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--action-hover);
}

.btn-primary:disabled {
  background-color: var(--text-secondary);
  opacity: 0.7;
  cursor: not-allowed;
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
}

.btn-secondary:hover {
  background-color: var(--bg-canvas);
}

.btn-danger {
  background-color: transparent;
  color: var(--status-error);
  border: 1px solid var(--status-error);
}

.btn-danger:hover {
  background-color: var(--status-error-bg);
}

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

.btn-danger-solid:hover {
  background-color: #dc2626;
}

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

.btn-sm {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  width: auto;
}

/* Status & Badges */
.status-badge {
  display: inline-block;
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  font-weight: 600;
}

.status-success {
  background-color: var(--status-success-bg);
  color: var(--status-success);
}

.status-error {
  background-color: var(--status-error-bg);
  color: var(--status-error);
}

/* Payment Items List */
.payments-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.payment-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-4);
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: border-color 0.2s;
}

.payment-item.paid {
  border-left: 4px solid var(--status-success);
}

.payment-item-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}

.payment-amount {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--text-primary);
}

.payment-order {
  font-size: var(--text-sm);
  color: var(--text-secondary);
}

.payment-actions {
  display: flex;
  gap: var(--space-2);
  align-items: center;
}

.payment-link {
  font-size: var(--text-sm);
  color: var(--action-primary);
  text-decoration: none;
  word-break: break-all;
}

.payment-link:hover {
  text-decoration: underline;
}

/* Utilities */
.text-center { text-align: center; }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.flex { display: flex; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }
.gap-4 { gap: var(--space-4); }

/* Icons */
.icon-large {
  font-size: var(--text-4xl);
  margin-bottom: var(--space-4);
  display: inline-block;
}
.icon-success { color: var(--status-success); }
.icon-error { color: var(--status-error); }

/* Dynamic items (index.html) */
.item-row {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  align-items: flex-end;
}
.item-row .form-group {
  margin-bottom: 0;
  flex: 1;
}
.item-row .qty-group {
  flex: 0 0 80px;
}
.item-row .price-group {
  flex: 0 0 100px;
}
.remove-item-btn {
  flex: 0 0 auto;
  padding: var(--space-3);
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--status-error);
  border-radius: var(--radius-md);
  cursor: pointer;
}
.remove-item-btn:hover {
  background: var(--status-error-bg);
}

/* Loading overlay */
.loading-overlay {
  display: none;
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(255,255,255,0.8);
  justify-content: center;
  align-items: center;
  z-index: 1000;
  flex-direction: column;
}
.loading-overlay.active {
  display: flex;
}
.spinner {
  width: 40px; height: 40px;
  border: 4px solid var(--border-subtle);
  border-top-color: var(--action-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: var(--space-4);
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* Modals */
.modal {
  display: none;
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.5);
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--space-4);
}
.modal.active {
  display: flex;
}
.modal-content {
  background: var(--bg-surface);
  padding: var(--space-6);
  border-radius: var(--radius-lg);
  max-width: 400px;
  width: 100%;
  box-shadow: var(--shadow-md);
}
.modal-actions {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

/* Error message */
.error-msg {
  color: var(--status-error);
  font-size: var(--text-sm);
  margin-top: var(--space-2);
  text-align: center;
}

/* Mobile Responsive */
@media (max-width: 600px) {
  .layout-dashboard {
    padding: var(--space-3);
  }
  
  .card {
    padding: var(--space-4);
  }
  
  .card-dashboard {
    margin-bottom: var(--space-4);
  }
  
  h1 {
    font-size: var(--text-xl);
    margin-bottom: var(--space-4);
  }
  
  .flex.justify-between.align-center {
    flex-direction: column;
    gap: var(--space-3);
    align-items: stretch;
  }
  
  .flex.justify-between.align-center h1 {
    text-align: center;
    margin-bottom: 0;
  }
  
  .flex.justify-between.align-center button {
    width: 100%;
  }
  
  .payment-item {
    padding: var(--space-3);
  }
  
  .payment-item-header {
    flex-direction: column;
    gap: var(--space-2);
  }
  
  .payment-item-header > div:last-child {
    text-align: left !important;
  }
  
  .payment-actions {
    flex-direction: column;
    gap: var(--space-2);
    align-items: stretch !important;
  }
  
  .payment-actions > div {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
  }
  
  .payment-actions .payment-link,
  .payment-actions button {
    flex: 1;
    text-align: center;
    min-width: 100px;
  }
  
  .payment-link {
    display: block;
    text-align: center;
    padding: var(--space-2);
    background: var(--bg-canvas);
    border-radius: var(--radius-sm);
  }
  
  .modal-content {
    padding: var(--space-4);
  }
  
  .modal-actions {
    flex-direction: column;
  }
  
  .modal-actions .btn {
    width: 100%;
  }
}