* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: #f5f7fa;
            color: #333;
        }
        
        /* Login Page Styles */
        .login-container {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            background: linear-gradient(135deg, #3498db, #2c3e50);
        }
        
        .login-card {
            background-color: white;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
            width: 100%;
            max-width: 400px;
            padding: 40px;
        }
        
        .login-header {
            text-align: center;
            margin-bottom: 30px;
        }
        
        .login-header h1 {
            font-size: 28px;
            color: #2c3e50;
            margin-bottom: 10px;
        }
        
        .login-header p {
            color: #7f8c8d;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
        }
        
        .form-control {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 14px;
            transition: border 0.3s;
        }
        
        .form-control:focus {
            border-color: #3498db;
            outline: none;
        }
        
        .btn {
            width: 100%;
            padding: 12px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            font-size: 16px;
            font-weight: 500;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }
        
        .btn i {
            margin-right: 8px;
        }
        
        .btn-primary {
            background-color: #3498db;
            color: white;
        }
        
        .btn-primary:hover {
            background-color: #2980b9;
        }
        
        .btn-block {
            display: block;
            width: 100%;
        }
        
        .login-footer {
            text-align: center;
            margin-top: 20px;
        }
        
        .login-footer a {
            color: #3498db;
            text-decoration: none;
        }
        
        .login-footer a:hover {
            text-decoration: underline;
        }
        
        /* Main App Styles */
        .app-container {
            display: none;
        }
        
        .container {
            display: flex;
            min-height: 100vh;
        }
        
        /* Sidebar Styles */
        .sidebar {
            width: 260px;
            background-color: #2c3e50;
            color: white;
            padding: 20px 0;
            position: fixed;
            height: 100vh;
            overflow-y: auto;
        }
        
        .logo {
            text-align: center;
            padding: 15px 0;
            border-bottom: 1px solid #34495e;
            margin-bottom: 20px;
        }
        
        .logo h2 {
            font-size: 24px;
            font-weight: 600;
        }
        
        .nav-menu {
            list-style: none;
        }
        
        .nav-item {
            padding: 12px 25px;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
        }
        
        .nav-item:hover {
            background-color: #34495e;
        }
        
        .nav-item.active {
            background-color: #3498db;
            border-left: 4px solid #2980b9;
        }
        
        .nav-item i {
            margin-right: 12px;
            font-size: 18px;
        }
        
        /* Main Content Styles */
        .main-content {
            margin-left: 260px;
            padding: 30px;
            width: calc(100% - 260px);
        }
        
        .header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 30px;
            padding-bottom: 15px;
            border-bottom: 1px solid #ddd;
        }
        
        .header h1 {
            font-size: 28px;
            font-weight: 600;
            color: #2c3e50;
        }
        
        .user-info {
            display: flex;
            align-items: center;
        }
        
        .user-info img {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            margin-right: 12px;
        }
        
        .user-info span {
            font-weight: 500;
        }
        
        .logout-btn {
            background: none;
            border: none;
            color: #e74c3c;
            cursor: pointer;
            font-size: 14px;
            margin-left: 15px;
            padding: 5px 10px;
            border-radius: 4px;
            transition: background-color 0.3s;
        }
        
        .logout-btn:hover {
            background-color: #f8f9fa;
        }
        
        /* Card Styles */
        .card {
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            padding: 25px;
            margin-bottom: 25px;
        }
        
        .card-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
        }
        
        .card-title {
            font-size: 20px;
            font-weight: 600;
            color: #2c3e50;
        }
        
        /* Dashboard Stats */
        .stats-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }
        
        .stat-card {
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
            padding: 20px;
            display: flex;
            align-items: center;
        }
        
        .stat-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-right: 15px;
            font-size: 24px;
            color: white;
        }
        
        .stat-icon.blue {
            background-color: #3498db;
        }
        
        .stat-icon.green {
            background-color: #2ecc71;
        }
        
        .stat-icon.orange {
            background-color: #f39c12;
        }
        
        .stat-icon.red {
            background-color: #e74c3c;
        }
        
        .stat-info h3 {
            font-size: 24px;
            font-weight: 600;
            margin-bottom: 5px;
        }
        
        .stat-info p {
            color: #7f8c8d;
            font-size: 14px;
        }
        
        /* Form Styles */
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
        }
        
        .form-control {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 14px;
            transition: border 0.3s;
        }
        
        .form-control:focus {
            border-color: #3498db;
            outline: none;
        }
        
        .btn {
            padding: 10px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            font-size: 14px;
            font-weight: 500;
            transition: all 0.3s;
            display: inline-flex;
            align-items: center;
        }
        
        .btn i {
            margin-right: 8px;
        }
        
        .btn-primary {
            background-color: #3498db;
            color: white;
        }
        
        .btn-primary:hover {
            background-color: #2980b9;
        }
        
        .btn-success {
            background-color: #2ecc71;
            color: white;
        }
        
        .btn-success:hover {
            background-color: #27ae60;
        }
        
        .btn-danger {
            background-color: #e74c3c;
            color: white;
        }
        
        .btn-danger:hover {
            background-color: #c0392b;
        }
        
        .btn-warning {
            background-color: #f39c12;
            color: white;
        }
        
        .btn-warning:hover {
            background-color: #d68910;
        }
        
        /* Table Styles */
        .table-container {
            overflow-x: auto;
        }
        
        table {
            width: 100%;
            border-collapse: collapse;
        }
        
        th, td {
            padding: 12px 15px;
            text-align: left;
            border-bottom: 1px solid #ddd;
        }
        
        th {
            background-color: #f8f9fa;
            font-weight: 600;
            color: #2c3e50;
        }
        
        tr:hover {
            background-color: #f8f9fa;
        }
        
        /* Bill Creation Styles */
        .bill-products {
            margin-bottom: 20px;
        }
        
        .product-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px;
            border: 1px solid #ddd;
            border-radius: 4px;
            margin-bottom: 10px;
        }
        
        .product-info {
            flex-grow: 1;
        }
        
        .product-name {
            font-weight: 600;
            margin-bottom: 5px;
        }
        
        .product-details {
            color: #7f8c8d;
            font-size: 14px;
        }
        
        .product-price {
            font-weight: 600;
            margin-right: 15px;
        }
        
        .quantity-control {
            display: flex;
            align-items: center;
            margin-right: 15px;
        }
        
        .quantity-btn {
            width: 30px;
            height: 30px;
            border: 1px solid #ddd;
            background-color: #f8f9fa;
            border-radius: 4px;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .quantity-input {
            width: 50px;
            text-align: center;
            border: 1px solid #ddd;
            border-left: none;
            border-right: none;
            height: 30px;
        }
        
        .bill-summary {
            background-color: #f8f9fa;
            padding: 20px;
            border-radius: 4px;
            margin-top: 20px;
        }
        
        .summary-row {
            display: flex;
            justify-content: space-between;
            margin-bottom: 10px;
        }
        
        .summary-row.total {
            font-weight: 600;
            font-size: 18px;
            border-top: 1px solid #ddd;
            padding-top: 10px;
            margin-top: 10px;
        }
        
        /* Invoice Styles */
        .invoice-container {
            display: none;
            background-color: white;
            padding: 40px;
            max-width: 800px;
            margin: 0 auto;
            box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
        }
        
        .invoice-header {
            display: flex;
            justify-content: space-between;
            margin-bottom: 30px;
            border-bottom: 1px solid #ddd;
            padding-bottom: 20px;
        }
        
        .invoice-logo h2 {
            font-size: 28px;
            color: #2c3e50;
            margin-bottom: 5px;
        }
        
        .invoice-logo p {
            color: #7f8c8d;
        }
        
        .invoice-details {
            text-align: right;
        }
        
        .invoice-details h3 {
            font-size: 20px;
            margin-bottom: 10px;
        }
        
        .invoice-details p {
            margin-bottom: 5px;
        }
        
        .invoice-customer {
            display: flex;
            justify-content: space-between;
            margin-bottom: 30px;
        }
        
        .invoice-customer-left h4, .invoice-customer-right h4 {
            font-size: 16px;
            margin-bottom: 10px;
            color: #2c3e50;
        }
        
        .invoice-customer-left p, .invoice-customer-right p {
            margin-bottom: 5px;
        }
        
        .invoice-table {
            width: 100%;
            margin-bottom: 30px;
        }
        
        .invoice-table th, .invoice-table td {
            padding: 12px;
            text-align: left;
            border-bottom: 1px solid #ddd;
        }
        
        .invoice-table th {
            background-color: #f8f9fa;
            font-weight: 600;
        }
        
        .invoice-summary {
            display: flex;
            justify-content: flex-end;
            margin-bottom: 30px;
        }
        
        .invoice-summary-table {
            width: 300px;
        }
        
        .invoice-summary-table tr td {
            padding: 8px 0;
        }
        
        .invoice-summary-table tr.total td {
            font-weight: 600;
            font-size: 18px;
            border-top: 1px solid #ddd;
            padding-top: 10px;
        }
        
        .invoice-footer {
            text-align: center;
            margin-top: 40px;
            padding-top: 20px;
            border-top: 1px solid #ddd;
            font-size: 14px;
            color: #7f8c8d;
        }
        
        .invoice-actions {
            display: flex;
            justify-content: center;
            margin-top: 30px;
            gap: 15px;
        }
        
        /* Hidden Sections */
        .section {
            display: none;
        }
        
        .section.active {
            display: block;
        }
        
        /* Responsive */
        @media (max-width: 992px) {
            .sidebar {
                width: 200px;
            }
            
            .main-content {
                margin-left: 200px;
                width: calc(100% - 200px);
            }
        }
        
        @media (max-width: 768px) {
            .sidebar {
                transform: translateX(-100%);
                transition: transform 0.3s;
            }
            
            .sidebar.open {
                transform: translateX(0);
            }
            
            .main-content {
                margin-left: 0;
                width: 100%;
            }
            
            .menu-toggle {
                display: block;
            }
            
            .invoice-header {
                flex-direction: column;
            }
            
            .invoice-details {
                text-align: left;
                margin-top: 20px;
            }
            
            .invoice-customer {
                flex-direction: column;
            }
            
            .invoice-customer-right {
                margin-top: 20px;
            }
            
            .invoice-summary {
                justify-content: flex-start;
            }
        }
        
        .menu-toggle {
            display: none;
            background: none;
            border: none;
            font-size: 24px;
            cursor: pointer;
            color: #2c3e50;
        }
        
        /* Search and Filter */
        .search-filter {
            display: flex;
            margin-bottom: 20px;
        }
        
        .search-input {
            flex-grow: 1;
            padding: 10px 15px;
            border: 1px solid #ddd;
            border-radius: 4px 0 0 4px;
            font-size: 14px;
        }
        
        .search-btn {
            padding: 10px 15px;
            background-color: #3498db;
            color: white;
            border: none;
            border-radius: 0 4px 4px 0;
            cursor: pointer;
        }
        
        /* Notification */
        .notification {
            position: fixed;
            top: 20px;
            right: 20px;
            padding: 15px 20px;
            background-color: #2ecc71;
            color: white;
            border-radius: 4px;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            z-index: 1000;
            transform: translateY(-100px);
            opacity: 0;
            transition: all 0.3s;
        }
        
        .notification.show {
            transform: translateY(0);
            opacity: 1;
        }
        
        .notification.error {
            background-color: #e74c3c;
        }
        
        /* Print Styles */
        @media print {
            body * {
                visibility: hidden;
            }
            
            .invoice-container, .invoice-container * {
                visibility: visible;
            }
            
            .invoice-container {
                position: absolute;
                left: 0;
                top: 0;
                width: 100%;
                box-shadow: none;
            }
            
            .invoice-actions {
                display: none;
            }
        }