/* Modern CSS Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Variables */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --background-color: #0f172a;
    --surface-color: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #334155;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-dark: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    --glow-primary: 0 0 20px rgba(99, 102, 241, 0.3);
    --glow-secondary: 0 0 20px rgba(139, 92, 246, 0.3);
}

/* Base Styles */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--gradient-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

/* Loading animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Fade in animation */
.fade-in {
    animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Pulse animation */
.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* Bounce animation */
.bounce {
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(20px);
    background: rgba(30, 41, 59, 0.9);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, #667eea, #764ba2, #f093fb);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    position: relative;
    transition: var(--transition);
    text-shadow: 0 0 30px rgba(102, 126, 234, 0.5);
}

.logo:hover {
    transform: scale(1.05);
    text-shadow: 0 0 40px rgba(102, 126, 234, 0.8);
}

.logo::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
}

.logo:hover::after {
    width: 100%;
}

.nav {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.1), transparent);
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    background: rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

.nav-link:hover::before,
.nav-link.active::before {
    left: 100%;
}

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

/* Main Content */
.main {
    padding: 2rem 0;
    min-height: calc(100vh - 80px);
}

.dashboard-header {
    margin-bottom: 2rem;
}

.dashboard-header h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.dashboard-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--surface-color);
    padding: 1.5rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    transition: var(--transition-slow);
}

.stat-card:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: var(--shadow-xl);
}

.stat-card:hover::before {
    left: 100%;
}

.stat-card:nth-child(1) {
    border-top: 4px solid #667eea;
}

.stat-card:nth-child(2) {
    border-top: 4px solid #f093fb;
}

.stat-card:nth-child(3) {
    border-top: 4px solid #4facfe;
}

.stat-card:nth-child(4) {
    border-top: 4px solid #43e97b;
}

.stat-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 50%;
    color: white;
    transition: var(--transition);
}

.stat-card:hover .stat-icon {
    transform: rotate(15deg) scale(1.1);
}

.stat-content h3 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

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

/* Products Grid */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.product-card {
    background: var(--surface-color);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-left: 4px solid transparent;
    position: relative;
    overflow: hidden;
    cursor: pointer;
}

.product-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: var(--transition);
}

.product-card:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: var(--shadow-xl);
}

.product-card:hover::before {
    transform: scaleX(1);
}

.product-card.warning {
    border-left-color: var(--warning-color);
    background: rgba(245, 158, 11, 0.05);
    animation: pulseWarning 2s infinite;
}

@keyframes pulseWarning {
    0%, 100% { box-shadow: var(--shadow); }
    50% { box-shadow: 0 0 20px rgba(245, 158, 11, 0.3); }
}

.product-card.warning {
    border-left-color: var(--warning-color);
    background: rgba(245, 158, 11, 0.05);
}

.product-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.product-header h4 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    flex: 1;
}

.product-category {
    background: var(--gradient-primary);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    transition: var(--transition);
}

.product-card:hover .product-category {
    transform: scale(1.1);
}

.product-info {
    margin-bottom: 1rem;
}

.product-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.product-price {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

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

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

.stock-warning {
    margin-left: 0.25rem;
}

.product-barcode {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-family: monospace;
}

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

/* Forms */
.form-section {
    background: var(--surface-color);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.form-section h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.3rem;
}

.product-form,
.auth-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--surface-light);
    color: var(--text-primary);
    backdrop-filter: blur(10px);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

/* Buttons */
.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: var(--transition-slow);
}

.btn-primary:hover {
    background: var(--gradient-primary);
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.5);
}

.btn-primary:hover::before {
    left: 100%;
}

.btn-primary:active {
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--gradient-secondary);
    color: white;
    position: relative;
    overflow: hidden;
}

.btn-secondary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition-slow);
}

.btn-secondary:hover {
    background: var(--gradient-secondary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary:hover::before {
    left: 100%;
}

.btn-danger {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.btn-danger::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition-slow);
}

.btn-danger:hover {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-danger:hover::before {
    left: 100%;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

.btn-full {
    width: 100%;
}

/* Alerts */
.alert {
    padding: 1.25rem;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
    border-left: 4px solid;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.alert-success {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.15), transparent);
    border-left-color: var(--success-color);
    color: #10b981;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.2);
}

.alert-error {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.15), transparent);
    border-left-color: var(--error-color);
    color: #ef4444;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.2);
}

.alert-warning {
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.15), transparent);
    border-left-color: var(--warning-color);
    color: #f59e0b;
    box-shadow: 0 4px 15px rgba(245, 158, 11, 0.2);
}

/* Auth Pages */
.auth-page {
    background: var(--gradient-primary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    position: relative;
    overflow: hidden;
}

.auth-page::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: float 20s infinite linear;
}

@keyframes float {
    0% { transform: translate(0, 0) rotate(0deg); }
    100% { transform: translate(-50px, -50px) rotate(360deg); }
}

.auth-container {
    width: 100%;
    max-width: 400px;
}

.auth-card {
    background: var(--surface-color);
    padding: 2.5rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
    position: relative;
    z-index: 1;
    backdrop-filter: blur(20px);
    background: rgba(30, 41, 59, 0.95);
    border: 1px solid rgba(255, 255, 255, 0.1);
    animation: slideUp 0.6s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header h1 {
    font-size: 2rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.auth-footer {
    text-align: center;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.auth-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    position: relative;
}

.auth-footer a:hover {
    color: var(--text-primary);
    text-decoration: none;
}

.auth-footer a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
}

.auth-footer a:hover::after {
    width: 100%;
}

.demo-accounts {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), transparent);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.demo-accounts h3 {
    font-size: 1rem;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.demo-accounts p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

/* Admin Section */
.admin-section {
    background: var(--surface-color);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.admin-section h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.3rem;
}

/* Table */
.table-container {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--surface-color);
}

.data-table th,
.data-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.data-table th {
    background: rgba(37, 99, 235, 0.05);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.data-table tr:hover {
    background: rgba(37, 99, 235, 0.02);
}

/* Badges */
.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.badge-admin {
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary-color);
}

.badge-user {
    background: rgba(100, 116, 139, 0.1);
    color: var(--secondary-color);
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 0.5rem;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: var(--surface-color);
    margin: 5% auto;
    padding: 0;
    border-radius: var(--border-radius-lg);
    width: 90%;
    max-width: 600px;
    box-shadow: var(--shadow-lg);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    margin: 0;
    color: var(--text-primary);
}

.close {
    color: var(--text-secondary);
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
}

.close:hover {
    color: var(--text-primary);
}

.modal-footer {
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
}

/* Checkbox */
.checkbox-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    gap: 0.5rem;
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark::after {
    content: '✓';
    color: white;
    font-size: 0.8rem;
    font-weight: bold;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

/* Alert Section */
.alert-section {
    margin-bottom: 2rem;
}

.low-stock-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background-color);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Focus styles for accessibility */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Selection styles */
::selection {
    background: var(--primary-color);
    color: white;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    .nav {
        gap: 1rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .products-grid {
        grid-template-columns: 1fr;
    }

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

    .action-buttons {
        flex-direction: column;
    }

    .modal-content {
        width: 95%;
        margin: 10% auto;
    }

    .data-table {
        font-size: 0.9rem;
    }

    .data-table th,
    .data-table td {
        padding: 0.75rem 0.5rem;
    }
}