* {
    box-sizing: border-box;
}

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

header {
    text-align: center;
    padding: 1em;
    background-color: #333;
    color: #fff;
}

header h1 {
    margin: 0;
}

nav ul {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0;
    list-style: none;
    background-color: #444;
    margin: 0;
}

nav ul li {
    margin: 0.5em;
}

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

main {
    max-width: 800px;
    margin: auto;
    padding: 1em;
}

section {
    margin-bottom: 2em;
    padding: 1em;
    border: 1px solid #ddd;
    border-radius: 5px;
}

section img {
    max-width: 100%;
    height: auto;
    border-radius: 5px;
}

footer {
    text-align: center;
    padding: 1em;
    background-color: #333;
    color: #fff;
    position: relative;
    bottom: 0;
    width: 100%;
}

/* Responsive Design */
@media (max-width: 600px) {
    nav ul {
        flex-direction: column;
    }

    section {
        text-align: center;
    }
}