:root {
    --primary-color: #007AFF;
    --secondary-color: #5856D6;
    --success-color: #34C759;
    --danger-color: #FF3B30;
    --warning-color: #FF9500;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F2F2F7;
    --bg-tertiary: #FFFFFF;
    --text-primary: #000000;
    --text-secondary: #8E8E93;
    --border-color: #E5E5EA;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #1C1C1E;
    --bg-tertiary: #2C2C2E;
    --text-primary: #FFFFFF;
    --text-secondary: #8E8E93;
    --border-color: #38383A;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

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

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow);
    z-index: 1000;
    padding: 1rem 0;
    transition: all 0.3s;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
    list-style: none;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    text-align: center;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: #0051D5;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

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

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

/* Cards */
.card {
    background: var(--bg-primary);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: all 0.3s;
    border: 1px solid var(--border-color);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.product-card {
    overflow: hidden;
    cursor: pointer;
}

.product-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 12px;
    margin-bottom: 1rem;
}

.product-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.product-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.product-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* Grid */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

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

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

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

/* Hero Section */
.hero {
    margin-top: 80px;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Theme Toggle */
.theme-toggle {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 0.5rem 1rem;
    cursor: pointer;
    color: var(--text-primary);
    font-size: 1.2rem;
    transition: all 0.3s;
}

.theme-toggle:hover {
    background: var(--bg-tertiary);
}

/* Product Detail */
.product-detail {
    margin-top: 100px;
    padding: 2rem 0;
}

.product-detail-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    margin-top: 2rem;
}

.product-gallery {
    position: relative;
}

.product-gallery img {
    width: 100%;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.product-info h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.product-info .price {
    font-size: 2rem;
    color: var(--primary-color);
    font-weight: 700;
    margin: 1rem 0;
}

.product-info .description {
    color: var(--text-secondary);
    line-height: 1.8;
    margin: 1.5rem 0;
}

/* Chat */
.chat-container {
    max-width: 800px;
    margin: 100px auto 2rem;
    height: 600px;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    background: var(--bg-secondary);
}

.message {
    margin-bottom: 1rem;
    display: flex;
    flex-direction: column;
}

.message.user {
    align-items: flex-end;
}

.message.admin {
    align-items: flex-start;
}

.message-bubble {
    max-width: 70%;
    padding: 1rem;
    border-radius: 16px;
    word-wrap: break-word;
}

.message.user .message-bubble {
    background: var(--primary-color);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.admin .message-bubble {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
}

.message-time {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.chat-input-area {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 1rem;
}

.chat-input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    background: var(--bg-secondary);
    color: var(--text-primary);
}

/* Admin Dashboard */
.dashboard {
    margin-top: 80px;
    padding: 2rem 0;
}

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

.stat-card {
    background: var(--bg-primary);
    padding: 1.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0.5rem 0;
}

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

.dashboard-section {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

.dashboard-section h2 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

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

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

.table th {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 10px;
    margin-bottom: 1rem;
}

.alert-success {
    background: rgba(52, 199, 89, 0.1);
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

.alert-error {
    background: rgba(255, 59, 48, 0.1);
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
}

.alert-info {
    background: rgba(0, 122, 255, 0.1);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

/* Responsive */
@media (max-width: 768px) {
    .products-grid {
        grid-template-columns: 1fr;
    }
    
    .product-detail-grid {
        grid-template-columns: 1fr;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .nav-links {
        gap: 1rem;
        font-size: 0.9rem;
    }
    
    .dashboard-stats {
        grid-template-columns: 1fr;
    }
    
    .table {
        font-size: 0.85rem;
    }
    
    .table th,
    .table td {
        padding: 0.5rem;
    }
}

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

.fade-in {
    animation: fadeIn 0.5s ease-out;
}

/* Loading */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(0, 122, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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