/* ============================================
   CSS Variables for Light & Dark Theme
   ============================================ */
:root {
    --primary-color: #2563eb;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-color: #ffffff;
    --text-color: #1f2937;
    --border-color: #e5e7eb;
    --hover-bg: #f3f4f6;
    --card-bg: #ffffff;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1f2937;
    --text-color: #f9fafb;
    --border-color: #374151;
    --hover-bg: #374151;
    --card-bg: #2d3748;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
}

/* ============================================
   Global Styles
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* ============================================
   Navigation Bar
   ============================================ */
.navbar {
    background-color: var(--card-bg);
    box-shadow: var(--shadow-lg);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-left {
    display: flex;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.theme-toggle:hover {
    transform: rotate(20deg);
}

.nav-links {
    display: flex;
    gap: 1rem;
    align-items: center;
}

/* ============================================
   Buttons
   ============================================ */
.btn,
.btn-small,
.btn-full,
.btn-copy,
.theme-toggle {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    text-decoration: none;
    display: inline-block;
}

.btn {
    padding: 0.75rem 2rem;
}

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

.btn-full {
    width: 100%;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background-color: #059669;
    transform: translateY(-2px);
}

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

.btn-danger:hover {
    background-color: #dc2626;
    transform: translateY(-2px);
}

.btn-copy {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    background-color: var(--hover-bg);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
}

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

/* ============================================
   Hero Section
   ============================================ */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 6rem 2rem;
    text-align: center;
}

.hero-content h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-buttons .btn {
    padding: 0.875rem 2.5rem;
    font-size: 1.1rem;
}

/* ============================================
   Features Section
   ============================================ */
.features {
    max-width: 1200px;
    margin: 4rem auto;
    padding: 0 2rem;
}

.features h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-card {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

/* ============================================
   Container & Layout
   ============================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

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

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.page-header p {
    color: #6b7280;
    font-size: 1.1rem;
}

/* ============================================
   Forms & Inputs
   ============================================ */
.form {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

.form-horizontal {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group:last-child {
    margin-bottom: 0;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.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(37, 99, 235, 0.1);
}

/* ============================================
   Authentication Pages
   ============================================ */
.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 80px);
    padding: 2rem;
}

.auth-box {
    background-color: var(--card-bg);
    padding: 3rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 500px;
}

.auth-box h2 {
    text-align: center;
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.auth-subtitle {
    text-align: center;
    color: #6b7280;
    margin-bottom: 2rem;
}

.auth-link {
    text-align: center;
    margin-top: 1.5rem;
}

.auth-link a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.auth-link a:hover {
    text-decoration: underline;
}

/* ============================================
   Inventory Section
   ============================================ */
.add-product-section,
.settings-section,
.danger-zone {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

.add-product-section h2,
.settings-section h2,
.danger-zone h2 {
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.search-section {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    align-items: center;
}

.search-box {
    flex: 1;
    min-width: 250px;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
}

.search-box:focus {
    outline: none;
    border-color: var(--primary-color);
}

.filter-select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
}

/* ============================================
   Products Table
   ============================================ */
.products-section {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.products-section h2 {
    margin-bottom: 1.5rem;
}

.table-responsive {
    overflow-x: auto;
}

.products-table {
    width: 100%;
    border-collapse: collapse;
}

.products-table thead {
    background-color: var(--hover-bg);
}

.products-table th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--text-color);
    border-bottom: 2px solid var(--border-color);
}

.products-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.products-table tbody tr:hover {
    background-color: var(--hover-bg);
    transition: background-color 0.3s ease;
}

.action-buttons {
    display: flex;
    gap: 0.5rem;
}

.action-buttons button {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 0.4rem;
    cursor: pointer;
    font-size: 0.85rem;
    transition: all 0.3s ease;
}

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

.btn-edit:hover {
    background-color: #1d4ed8;
}

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

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

.no-products {
    text-align: center;
    padding: 3rem;
    color: #6b7280;
}

/* ============================================
   Profile Section
   ============================================ */
.profile-section {
    margin-bottom: 3rem;
}

.profile-card {
    background-color: var(--card-bg);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.profile-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem;
    text-align: center;
}

.profile-avatar {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.profile-header h2 {
    margin: 0;
    font-size: 2rem;
}

.profile-info {
    padding: 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.info-group {
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.info-group:last-child {
    border-bottom: none;
}

.info-group label {
    display: block;
    font-weight: 600;
    color: #6b7280;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.info-value {
    font-size: 1.25rem;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.profile-stats {
    background-color: var(--hover-bg);
    padding: 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.9rem;
    color: #6b7280;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ============================================
   Settings Card
   ============================================ */
.settings-card {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    border: 1px solid var(--border-color);
}

.settings-card h3 {
    margin-bottom: 1.5rem;
}

/* ============================================
   Danger Zone
   ============================================ */
.danger-card {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    border: 2px solid var(--danger-color);
}

.danger-card h3 {
    color: var(--danger-color);
    margin-bottom: 0.5rem;
}

.danger-card p {
    color: #6b7280;
    margin-bottom: 1.5rem;
}

/* ============================================
   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);
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    justify-content: center;
    align-items: center;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.modal-content {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    width: 90%;
    max-width: 600px;
    position: relative;
    animation: slideIn 0.3s ease;
}

.modal-small {
    max-width: 400px;
}

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

.close {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 2rem;
    cursor: pointer;
    color: #6b7280;
    transition: color 0.3s ease;
}

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

.modal-content h2 {
    margin-bottom: 1.5rem;
}

.modal-buttons {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
}

.modal-buttons button {
    flex: 1;
}

/* ============================================
   Messages
   ============================================ */
.message {
    padding: 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    display: none;
    animation: slideIn 0.3s ease;
}

.message.show {
    display: block;
}

.message.success {
    background-color: #d1fae5;
    color: #065f46;
    border-left: 4px solid var(--secondary-color);
}

.message.error {
    background-color: #fee2e2;
    color: #7f1d1d;
    border-left: 4px solid var(--danger-color);
}

.message.warning {
    background-color: #fef3c7;
    color: #78350f;
    border-left: 4px solid var(--warning-color);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-color);
    padding: 2rem;
    text-align: center;
    color: #6b7280;
    margin-top: 4rem;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem;
    }

    .nav-links {
        gap: 0.5rem;
    }

    .btn-small {
        padding: 0.4rem 0.8rem;
        font-size: 0.8rem;
    }

    .hero-content h2 {
        font-size: 2rem;
    }

    .hero-content p {
        font-size: 1rem;
    }

    .page-header h1 {
        font-size: 2rem;
    }

    .auth-box {
        padding: 2rem;
    }

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

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

    .search-section {
        flex-direction: column;
    }

    .search-box {
        width: 100%;
    }

    .modal-content {
        width: 95%;
    }

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

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

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

@media (max-width: 480px) {
    .container {
        padding: 1rem;
    }

    .logo {
        font-size: 1.2rem;
    }

    .hero {
        padding: 3rem 1rem;
    }

    .hero-content h2 {
        font-size: 1.5rem;
    }

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

    .hero-buttons .btn {
        width: 100%;
    }

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

    .auth-box {
        padding: 1.5rem;
    }

    .profile-header {
        padding: 1.5rem;
    }

    .profile-avatar {
        font-size: 3rem;
    }

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