/* ============ CSS Variables & Theme ============ */
:root {
    /* Dark Mode (Default) */
    --bg-primary: #0f1724;
    --bg-secondary: #1a2332;
    --bg-tertiary: #242e3d;
    --bg-card: #1e293b;
    --bg-hover: #2d3b4f;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #334155;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --info-color: #06b6d4;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.5);
    --transition: all 0.3s ease;
}

/* Light Mode */
[data-theme="light"] {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --bg-card: #ffffff;
    --bg-hover: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: var(--transition);
}

/* ============ Header ============ */
.header {
    background: var(--bg-secondary);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--accent-color);
    margin: 0;
}

.header-subtitle {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.connection-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border-radius: 20px;
    font-size: 0.85rem;
}

.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--danger-color);
    transition: var(--transition);
}

.status-dot.connected {
    background: var(--success-color);
    box-shadow: 0 0 10px var(--success-color);
}

.status-dot.connecting {
    background: var(--warning-color);
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.theme-toggle {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: var(--transition);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--bg-hover);
    transform: scale(1.1);
}

.user-info {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
}

.user-name {
    font-weight: 600;
    font-size: 0.9rem;
}

.user-role {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* ============ Main Container ============ */
.main-container {
    display: flex;
    height: calc(100vh - 73px);
    overflow: hidden;
}

/* ============ Sidebar ============ */
.sidebar {
    width: 200px;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    padding: 1rem 0;
    transition: var(--transition);
    overflow-y: auto;
}

.nav-list {
    list-style: none;
    padding: 0;
}

.nav-item {
    padding: 0.75rem 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-secondary);
    border-right: 3px solid transparent;
}

.nav-item:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.nav-item.active {
    background: var(--bg-tertiary);
    color: var(--accent-color);
    border-right-color: var(--accent-color);
    font-weight: 600;
}

.nav-icon {
    font-size: 1.2rem;
}

/* ============ Content Area ============ */
.content {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
    background: var(--bg-primary);
}

.page {
    display: none;
}

.page.active {
    display: block;
}

.page-title {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.8rem;
}

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.header-actions {
    display: flex;
    gap: 0.5rem;
}

/* ============ POS Toolbar ============ */
.pos-toolbar {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    align-items: center;
}

.search-box {
    flex: 1;
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.clear-search {
    position: absolute;
    left: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1.2rem;
    display: none;
}

.clear-search.visible {
    display: block;
}

.barcode-indicator {
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--success-color);
    font-size: 0.9rem;
    white-space: nowrap;
}
.barcode-box {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    flex: 1;
}

.barcode-box input {
    flex: 1;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 2px solid var(--accent-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: bold;
    letter-spacing: 1px;
    transition: var(--transition);
}

.barcode-box input:focus {
    outline: none;
    border-color: var(--success-color);
    box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.2);
}

.barcode-box input::placeholder {
    color: var(--text-muted);
    font-weight: normal;
    letter-spacing: 0;
}

.barcode-btn {
    padding: 0.75rem 1.5rem;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.barcode-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}
/* ============ Category Tabs ============ */
.category-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.category-tab {
    padding: 0.5rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.category-tab:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.category-tab.active {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

/* ============ Products Grid ============ */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    padding-bottom: 2rem;
}

.product-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-color);
}

.product-image {
    width: 100%;
    height: 150px;
    background: var(--bg-tertiary);
    border-radius: 8px;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    overflow: hidden;
}

.product-name {
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.product-price {
    color: var(--accent-color);
    font-weight: bold;
    font-size: 1.2rem;
}

.product-stock {
    position: absolute;
    top: 10px;
    right: 10px;
    background: var(--bg-tertiary);
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.product-stock.low {
    background: var(--danger-color);
    color: white;
}

.product-stock.expired {
    background: var(--warning-color);
    color: white;
}

/* ============ Settings Page ============ */
.settings-section {
    margin-bottom: 2rem;
}

.settings-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
}

.firebase-status {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.data-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.sync-info {
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: 8px;
}

.sync-info h4 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.sync-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.form-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
}

/* ============ Cart Panel ============ */
.cart-panel {
    width: 350px;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: var(--transition);
}

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

.cart-header h2 {
    font-size: 1.2rem;
}

.close-cart {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1.2rem;
    cursor: pointer;
    display: none;
}

.cart-items {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.cart-item {
    background: var(--bg-tertiary);
    border-radius: 8px;
    padding: 0.75rem;
    margin-bottom: 0.75rem;
}

.cart-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.cart-item-name {
    font-weight: 600;
    font-size: 0.9rem;
}

.cart-item-remove {
    background: none;
    border: none;
    color: var(--danger-color);
    cursor: pointer;
    font-size: 1rem;
}

.cart-item-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.quantity-control {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.quantity-btn {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    width: 30px;
    height: 30px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition);
}

.quantity-btn:hover {
    background: var(--bg-hover);
}

.quantity-value {
    font-weight: 600;
    min-width: 30px;
    text-align: center;
}

.cart-item-price {
    font-weight: bold;
    color: var(--accent-color);
}

.cart-footer {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
}

.cart-summary {
    margin-bottom: 1rem;
}

.summary-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.total-row {
    font-weight: bold;
    color: var(--text-primary);
    font-size: 1.2rem;
    border-top: 2px solid var(--border-color);
    padding-top: 0.5rem;
    margin-top: 0.5rem;
}

.cart-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-checkout {
    flex: 1;
    padding: 0.75rem;
    background: var(--success-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-checkout:hover {
    background: #059669;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-clear {
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
}

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

/* ============ Statistics Cards ============ */
.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: var(--transition);
}

.stat-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-3px);
}

.stat-icon {
    font-size: 2.5rem;
}

.stat-info h3 {
    font-size: 1.5rem;
    color: var(--accent-color);
    margin-bottom: 0.25rem;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ============ Alerts Section ============ */
.alerts-section,
.sales-log-section {
    margin-bottom: 2rem;
}

.section-title {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.3rem;
}

.alerts-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.alert-item {
    padding: 0.75rem 1rem;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.9rem;
}

.alert-item.expired {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
}

.alert-item.low-stock {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid var(--warning-color);
    color: var(--warning-color);
}

/* ============ Tables ============ */
.sales-table-container,
.products-table-container {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow-x: auto;
}

.sales-table,
.products-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.sales-table th,
.products-table th {
    background: var(--bg-tertiary);
    padding: 0.75rem 1rem;
    text-align: right;
    font-weight: 600;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

.sales-table td,
.products-table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

.sales-table tr:last-child td,
.products-table tr:last-child td {
    border-bottom: none;
}

.sales-table tbody tr:hover,
.products-table tbody tr:hover {
    background: var(--bg-hover);
}

/* ============ Buttons ============ */
.btn-primary {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
}

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

/* ============ Sales Filters ============ */
.sales-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.sales-filters select {
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
}

/* ============ Modal ============ */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: 12px;
    padding: 2rem;
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.modal-header h2 {
    font-size: 1.5rem;
}

.close-modal {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1.5rem;
    cursor: pointer;
}

/* ============ Form Styles ============ */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-color);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

/* ============ Checkout Success ============ */
.checkout-success {
    text-align: center;
}

.success-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.checkout-success h2 {
    margin-bottom: 1rem;
    color: var(--success-color);
}

.checkout-success p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* ============ Alert Categories ============ */
.alerts-categories {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.alert-category {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
}

.alert-category h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.alert-items-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

/* ============ Toast Notification ============ */
.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    opacity: 0;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ============ Utility Classes ============ */
.empty-cart {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
}

.no-products,
.no-alerts {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.text-center {
    text-align: center;
}

.status-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
}

.status-badge.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
}

.product-cell {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.product-thumbnail {
    font-size: 1.5rem;
}

.action-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.1rem;
    padding: 0.25rem;
    transition: var(--transition);
    border-radius: 4px;
}

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

.action-btn.edit:hover {
    background: rgba(59, 130, 246, 0.1);
}

.action-btn.delete:hover {
    background: rgba(239, 68, 68, 0.1);
}

.low {
    color: var(--warning-color);
    font-weight: 600;
}

.expired {
    color: var(--danger-color);
    font-weight: 600;
}

/* ============ Responsive Design ============ */
@media (max-width: 768px) {
    .main-container {
        flex-direction: column;
        height: auto;
    }
    
    .sidebar {
        width: 100%;
        order: -1;
    }
    
    .nav-list {
        display: flex;
        overflow-x: auto;
    }
    
    .nav-item {
        white-space: nowrap;
        padding: 0.5rem 1rem;
    }
    
    .cart-panel {
        width: 100%;
        height: 50vh;
        position: fixed;
        bottom: 0;
        right: 0;
        z-index: 200;
        transform: translateY(100%);
    }
    
    .cart-panel.open {
        transform: translateY(0);
    }
    
    .close-cart {
        display: block;
    }
    
    .products-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
    
    .alerts-categories {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .header-right {
        gap: 0.5rem;
    }
    
    .connection-status {
        display: none;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 0.75rem 1rem;
    }
    
    .logo {
        font-size: 1.2rem;
    }
    
    .header-subtitle {
        display: none;
    }
    
    .content {
        padding: 1rem;
    }
    
    .stats-container {
        grid-template-columns: 1fr;
    }
    
    .pos-toolbar {
        flex-direction: column;
    }
    
    .data-actions {
        flex-direction: column;
    }
}