body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

.container {
    width: 80%;
    margin: auto;
    padding: 20px;
}

header {
    background: #333;
    color: #fff;
    padding: 10px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header .logo img {
    height: 50px;
}

header nav ul {
    list-style: none;
    display: flex;
    margin: 0;
    padding: 0;
}

header nav ul li {
    margin: 0 10px;
}

header nav ul li a {
    color: #fff;
    text-decoration: none;
}

footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 10px 0;
    position: relative;
    bottom: 0;
    width: 100%;
}

.art-grid, .gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
}

.art-card, .gallery-item {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: center;
}

.art-card img, .gallery-item img {
    max-width: 100%;
    height: auto;
}

.btn {
    display: inline-block;
    padding: 10px 20px;
    background: #333;
    color: #fff;
    text-decoration: none;
    border-radius: 5px;
}

.btn:hover {
    background: #555;
}

.cart-table, .order-table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

.cart-table th, .cart-table td, .order-table th, .order-table td {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: left;
}

.error {
    color: red;
}

.success {
    color: green;
}

form div {
    margin-bottom: 15px;
}

form label {
    display: block;
    margin-bottom: 5px;
}

form input, form textarea, form select {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
}