styles.css

/* Modern Inventory App - Clean UI Design */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  /* Colors */
  --primary: #3b82f6;
  --primary-dark: #2563eb;
  --secondary: #64748b;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --info: #06b6d4;
  
  /* Backgrounds */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --bg-card: #ffffff;
  --bg-overlay: rgba(0, 0, 0, 0.5);
  
  /* Text */
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  --text-white: #ffffff;
  
  /* Borders */
  --border-light: #e2e8f0;
  --border-medium: #cbd5e1;
  --border-dark: #94a3b8;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  /* 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;
  --space-12: 3rem;
  --space-16: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  
  /* Transitions */
  --transition: all 0.2s ease-in-out;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

.flex {
  display: flex;
}

.grid {
  display: grid;
}

.hidden {
  display: none !important;
}

/* Sidebar */
.sidebar {
  position: fixed;
  left: 0;
  top: 0;
  width: 280px;
  height: 100vh;
  background: var(--bg-card);
  border-right: 1px solid var(--border-light);
  padding: var(--space-6);
  z-index: 100;
  overflow-y: auto;
}

.sidebar-header {
  margin-bottom: var(--space-8);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.sidebar-logo-icon {
  width: 40px;
  height: 40px;
  background: var(--primary);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  color: var(--text-white);
}

.sidebar-logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.sidebar-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.sidebar-nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius);
  transition: var(--transition);
  font-weight: 500;
}

.sidebar-nav-link:hover,
.sidebar-nav-link.active {
  background: var(--bg-tertiary);
  color: var(--primary);
}

.sidebar-nav-icon {
  font-size: 1.25rem;
}

.sidebar-footer {
  margin-top: auto;
  padding-top: var(--space-6);
}

.sidebar-logout-btn {
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--danger);
  color: var(--text-white);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 500;
  transition: var(--transition);
}

.sidebar-logout-btn:hover {
  background: #dc2626;
}

/* Main Content */
.main-content {
  margin-left: 280px;
  padding: var(--space-8);
  min-height: 100vh;
}

.main-header {
  margin-bottom: var(--space-8);
}

.main-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.main-subtitle {
  color: var(--text-secondary);
  font-size: 1.125rem;
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

/* Dashboard Cards */
.dashboard-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-8);
}

.dashboard-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-align: center;
  transition: var(--transition);
}

.dashboard-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.dashboard-card-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-4);
}

.dashboard-card-title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}

.dashboard-card-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

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

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

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

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

.btn-success {
  background: var(--success);
  color: var(--text-white);
}

.btn-success:hover {
  background: #059669;
}

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

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

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

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

.form-input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-size: 0.875rem;
  transition: var(--transition);
}

.form-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-input::placeholder {
  color: var(--text-muted);
}

/* Auth Pages */
.auth-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: var(--space-4);
}

.auth-card {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 400px;
}

.auth-header {
  text-align: center;
  margin-bottom: var(--space-8);
}

.auth-title {
  font-size: 1.875rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.auth-description {
  color: var(--text-secondary);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.auth-footer {
  margin-top: var(--space-6);
  text-align: center;
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-light);
}

/* Modals */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--space-4);
}

.modal-content {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
}

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

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-secondary);
  cursor: pointer;
  padding: var(--space-2);
  border-radius: var(--radius);
  transition: var(--transition);
}

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

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

th, td {
  padding: var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}

th {
  background: var(--bg-tertiary);
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.875rem;
}

tr:hover {
  background: var(--bg-secondary);
}

/* Inventory Specific */
.inventory-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-8);
  flex-wrap: wrap;
  gap: var(--space-4);
}

.header-actions {
  display: flex;
  gap: var(--space-3);
  align-items: center;
  flex-wrap: wrap;
}

.search-container {
  position: relative;
}

.search-container input {
  padding-right: 40px;
  min-width: 250px;
}

.search-icon {
  position: absolute;
  right: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-6);
}

.product-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: var(--transition);
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.product-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: var(--space-4);
}

.product-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.product-brand {
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: var(--space-2);
}

.product-details {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.detail-item {
  display: flex;
  flex-direction: column;
}

.detail-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-1);
}

.detail-value {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.product-actions {
  display: flex;
  gap: var(--space-2);
  justify-content: flex-end;
}

.btn-edit {
  background: var(--info);
  color: var(--text-white);
  padding: var(--space-2) var(--space-3);
  font-size: 0.75rem;
}

.btn-delete {
  background: var(--danger);
  color: var(--text-white);
  padding: var(--space-2) var(--space-3);
  font-size: 0.75rem;
}

/* Sales Specific */
.sales-product-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  padding: var(--space-3);
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
}

.sales-product-card:hover {
  background: var(--bg-tertiary);
  border-color: var(--primary);
}

.sales-product-card.selected {
  border-color: var(--primary);
  background: rgba(59, 130, 246, 0.1);
}

.cart-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3);
  border-bottom: 1px solid var(--border-light);
}

.cart-item:last-child {
  border-bottom: none;
}

/* Advanced Features */
.smart-alert {
  animation: slideInRight 0.3s ease;
}

.bulk-toolbar {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  display: flex;
  gap: var(--space-3);
  align-items: center;
}

.product-checkbox {
  position: absolute;
  top: var(--space-2);
  left: var(--space-2);
  accent-color: var(--primary);
}

/* Loading States */
.loading-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid rgba(59, 130, 246, 0.3);
  border-top: 3px solid var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

/* Toast Notifications */
.toast {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--success);
  color: white;
  padding: var(--space-4);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  max-width: 300px;
  animation: slideInRight 0.3s ease;
}

.toast.error {
  background: var(--danger);
}

.toast.warning {
  background: var(--warning);
}

/* Advanced Analytics */
.metric-card {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: white;
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  position: relative;
  overflow: hidden;
}

.metric-card::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 100px;
  height: 100px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  transform: translate(30px, -30px);
}

/* Supplier Cards */
.supplier-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: var(--transition);
  position: relative;
}

.supplier-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.supplier-status {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--success);
}

.supplier-status.inactive {
  background: var(--danger);
}

/* Enhanced Forms */
.form-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
  transform: translateY(-1px);
}

.form-input.error {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

/* Password Strength Indicator */
.password-strength {
  height: 4px;
  background: var(--border-light);
  border-radius: 2px;
  margin-top: var(--space-2);
  overflow: hidden;
}

.password-strength-bar {
  height: 100%;
  transition: var(--transition);
  border-radius: 2px;
}

.password-strength-weak { background: var(--danger); width: 25%; }
.password-strength-medium { background: var(--warning); width: 50%; }
.password-strength-strong { background: var(--success); width: 100%; }

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    --border-light: #334155;
  }
}

/* Print Styles */
@media print {
  .sidebar, .modal-overlay, .bulk-toolbar, .toast {
    display: none !important;
  }
  
  .main-content {
    margin-left: 0;
    padding: 0;
  }
  
  .card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ccc;
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }
  
  .sidebar.open {
    transform: translateX(0);
  }
  
  .main-content {
    margin-left: 0;
    padding: var(--space-4);
  }
  
  .main-title {
    font-size: 2rem;
  }
  
  .dashboard-cards {
    grid-template-columns: 1fr;
  }
  
  .inventory-header {
    flex-direction: column;
    align-items: stretch;
  }
  
  .header-actions {
    justify-content: center;
  }
  
  .search-container input {
    min-width: 200px;
  }
  
  .products-grid {
    grid-template-columns: 1fr;
  }
  
  .product-details {
    grid-template-columns: 1fr;
  }
  
  /* Sales page mobile */
  .grid[style*="2fr 1fr"] {
    grid-template-columns: 1fr !important;
  }
}

/* Performance Optimizations */
.product-card img {
  width: 100%;
  height: 120px;
  object-fit: cover;
  border-radius: var(--radius);
  margin-bottom: var(--space-4);
  background: var(--bg-tertiary);
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-4);
  contain: layout style;
}

.product-card {
  contain: layout style paint;
  will-change: transform;
}

/* Skeleton Loading */
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* Receipt Styles */
.receipt-container {
  max-width: 800px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: var(--space-8);
}

.receipt-preview {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow);
}

.receipt-paper {
  background: white;
  color: #000;
  padding: var(--space-8);
  border-radius: var(--radius);
  font-family: 'Courier New', monospace;
  max-width: 400px;
  margin: 0 auto;
  box-shadow: var(--shadow-md);
}

.receipt-header {
  text-align: center;
  margin-bottom: var(--space-6);
}

.business-name {
  font-size: 1.5rem;
  font-weight: bold;
  margin: var(--space-2) 0;
  color: #000;
}

.business-info {
  font-size: 0.875rem;
  line-height: 1.4;
}

.business-info p {
  margin: var(--space-1) 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
}

.receipt-divider {
  border-top: 1px dashed #000;
  margin: var(--space-4) 0;
}

.receipt-meta {
  margin-bottom: var(--space-4);
}

.receipt-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--space-1);
  font-size: 0.875rem;
}

.receipt-table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-4) 0;
  font-size: 0.875rem;
}

.receipt-table th,
.receipt-table td {
  padding: var(--space-2);
  text-align: left;
  border-bottom: 1px solid #ddd;
}

.receipt-table th {
  font-weight: bold;
  background: #f5f5f5;
}

.receipt-totals {
  margin-top: var(--space-4);
}

.total-row {
  font-size: 1rem;
  border-top: 1px solid #000;
  padding-top: var(--space-2);
  margin-top: var(--space-2);
}

.receipt-footer {
  text-align: center;
  margin-top: var(--space-6);
}

.thank-you {
  font-size: 1.125rem;
  font-weight: bold;
  margin-bottom: var(--space-2);
}

.return-policy {
  font-size: 0.75rem;
  color: #666;
  margin-bottom: var(--space-4);
}

.qr-code {
  margin-top: var(--space-4);
}

.qr-code p {
  font-size: 0.75rem;
  margin-top: var(--space-1);
  color: #666;
}

.receipt-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.receipt-actions .btn {
  width: 100%;
  justify-content: center;
}

@media (max-width: 768px) {
  .receipt-container {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }
  
  .receipt-actions {
    flex-direction: row;
    flex-wrap: wrap;
  }
  
  .receipt-actions .btn {
    flex: 1;
    min-width: 120px;
  }
}