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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f5f5f5;
}

/* Navigation */
.navbar {
    background: #2c3e50;
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo {
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
}

.nav-links a {
    color: white;
    text-decoration: none;
    margin: 0 15px;
}

.nav-links button {
    background: #3498db;
    color: white;
    border: none;
    padding: 8px 15px;
    margin-left: 10px;
    border-radius: 5px;
    cursor: pointer;
}

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

.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 80px 20px;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: bold;
    margin: 0 10px;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-secondary {
    background: white;
    color: #3498db;
}

/* Features */
.features {
    padding: 60px 20px;
    text-align: center;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.feature-card {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

/* Listings Grid */
.listings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.listing-card {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.listing-card:hover {
    transform: translateY(-5px);
}

.listing-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.seller-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.seller-rating {
    color: #f39c12;
    font-weight: bold;
}

.listing-price {
    font-size: 1.5rem;
    font-weight: bold;
    color: #27ae60;
}

.listing-specs {
    margin: 15px 0;
    padding: 10px 0;
    border-top: 1px solid #eee;
    border-bottom: 1px solid #eee;
}

.listing-specs p {
    margin: 5px 0;
}

.listing-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

.listing-actions button {
    flex: 1;
    padding: 8px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

.btn-favorite {
    background: #f39c12;
    color: white;
}

.btn-buy {
    background: #27ae60;
    color: white;
}

/* Filters */
.filters {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

.filters select {
    padding: 8px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

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

.modal-content {
    background: white;
    margin: 15% auto;
    padding: 30px;
    border-radius: 10px;
    max-width: 400px;
    position: relative;
}

.close {
    position: absolute;
    right: 20px;
    top: 10px;
    font-size: 28px;
    cursor: pointer;
}

/* Forms */
form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

input, textarea, select {
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

button {
    padding: 10px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

/* Star Rating */
.rating {
    display: flex;
    gap: 5px;
    margin: 10px 0;
}

.star {
    font-size: 24px;
    color: #ddd;
    cursor: pointer;
}

.star.active {
    color: #f39c12;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: flex;
        flex-wrap: wrap;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .filters {
        flex-direction: column;
    }
}