body {
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
    background-color: #111;
    color: #fff;
    transition: background-color 0.3s ease;
}

header {
    background-color: #333;
    padding: 10px 0;
    position: sticky;
    top: 0;
    z-index: 1;
}

.page-selection {
    list-style: none;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0;
    margin: 0;
}

.page-selection li {
    margin: 0 10px;
}

.page-selection a {
    text-decoration: none;
    color: #fff;
    transition: color 0.3s ease;
}

.page-selection a:hover {
    color: #00a0a0;
}

.content {
    padding: 20px;
}

h1, h2 {
    color: #00a0a0;
}

/* Dark mode styles */
body.dark-mode {
    background-color: #000;
    color: #ddd;
}

body.dark-mode header {
    background-color: #222;
}

body.dark-mode .page-selection a {
    color: #ddd;
}

body.dark-mode .page-selection a:hover {
    color: #00a0a0;
}