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

:root {
    --primary-color: #0066cc;
    --secondary-color: #f59e0b;
    --text-dark: #1f2937;
    --text-gray: #6b7280;
    --border-color: #e5e7eb;
    --background-light: #f9fafb;
}

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

/* Header & Navigation */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    text-decoration: none;
    color: white;
}

.logo:hover {
    opacity: 0.9;
}

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

nav a {
    color: white;
    text-decoration: none;
    transition: opacity 0.3s;
}

nav a:hover {
    opacity: 0.8;
}

/* Search Bar */
.search-box {
    display: flex;
    gap: 0.5rem;
    align-items: center;
    margin-bottom: 1rem;
}

.search-box input {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    width: 250px;
    font-size: 0.95rem;
}

.search-box button {
    padding: 0.5rem 1.5rem;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
    font-weight: 500;
}

.search-box button:hover {
    background-color: #d97706;
}

/* Filter Section */
.filter-section {
    background-color: var(--background-light);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
}

.filter-section h3 {
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.filter-section h4 {
    margin-top: 1rem;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    color: var(--text-dark);
}

/* Category Filter Buttons */
.category-filter {
    margin-top: 1.5rem;
}

.category-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.category-btn {
    padding: 0.5rem 1rem;
    background-color: white;
    color: var(--text-dark);
    border: 2px solid var(--border-color);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 0.9rem;
    font-weight: 500;
    white-space: nowrap;
}

.category-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

/* Main Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), #003d99);
    color: white;
    padding: 3rem 1rem;
    text-align: center;
    border-radius: 8px;
    margin-bottom: 2rem;
}

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

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Products Grid */
.products-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.product-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
    display: flex;
    flex-direction: column;
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.product-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background-color: var(--background-light);
}

.product-info {
    padding: 1rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.product-name {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
    line-height: 1.4;
    min-height: 2.8rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.product-brand {
    color: var(--text-gray);
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
}

.product-category {
    color: var(--text-gray);
    font-size: 0.75rem;
    margin-bottom: 0.5rem;
}

.product-price {
    font-size: 1.4rem;
    font-weight: bold;
    color: var(--secondary-color);
    margin: 0.5rem 0;
}

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

.btn-view {
    flex: 1;
    padding: 0.75rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
    font-weight: 500;
}

.btn-view:hover {
    background-color: #0052a3;
}

/* Product Detail Page */
.product-detail {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.product-detail-image {
    width: 100%;
    max-height: 500px;
    object-fit: cover;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.product-detail-info h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.product-detail-brand {
    color: var(--text-gray);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.product-detail-category {
    color: var(--text-gray);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.product-detail-price {
    font-size: 2rem;
    color: var(--secondary-color);
    font-weight: bold;
    margin-bottom: 1.5rem;
}

.product-detail-description {
    color: var(--text-dark);
    line-height: 1.8;
    margin-bottom: 2rem;
    max-height: 300px;
    overflow-y: auto;
}

.product-actions-detail {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.btn-buy {
    flex: 1;
    padding: 1rem;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color 0.3s;
}

.btn-buy:hover {
    background-color: #d97706;
}

.btn-back {
    flex: 1;
    padding: 1rem;
    background-color: var(--border-color);
    color: var(--text-dark);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color 0.3s;
}

.btn-back:hover {
    background-color: #d1d5db;
}

/* Loading & Empty State */
.loading {
    text-align: center;
    padding: 2rem;
    color: var(--text-gray);
}

.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-gray);
}

.empty-state h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

/* Filter Section */
.filter-section {
    background-color: var(--background-light);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
}

.filter-section h3 {
    margin-bottom: 1rem;
}

.filter-group {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.filter-group select,
.filter-group input {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

/* Footer */
footer {
    background-color: var(--text-dark);
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: 3rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .product-detail {
        grid-template-columns: 1fr;
    }
    
    .products-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: 1rem;
    }
    
    .header-container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .search-box input {
        width: 200px;
    }
    
    .hero h1 {
        font-size: 1.8rem;
    }
    
    nav {
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    .products-grid {
        grid-template-columns: 1fr;
    }
    
    .search-box {
        flex-direction: column;
        width: 100%;
    }
    
    .search-box input {
        width: 100%;
    }
    
    .product-actions-detail {
        flex-direction: column;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mt-2 {
    margin-top: 2rem;
}

.mb-2 {
    margin-bottom: 2rem;
}