body {
    font-family: Arial, sans-serif;
}

header {
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 20px;
}

nav ul {
    list-style: none;
    padding: 0;
}

nav li {
    display: inline;
    margin: 0 10px;
}

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

section {
    padding: 20px;
}

.product img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto;
}