body {
    background-color: #f8f8f8; 
    color: #333333; 
    margin: 10px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

main {
    width: 90%;
    max-width: 900px;
    margin: 30px auto;
    padding: 25px;
    background-color: #ffffff;
    border: 1px solid #ddd;
    border-radius: 8px;
}

h1 {
    text-align: center;
    padding-bottom: 5px;
    border-bottom: 2px solid #ccc;
}

h2 {
    text-align: center;
}

nav {
    text-align: center;
    padding: 15px 0;
    font-size: 1.1em;
}

nav a {
    text-decoration: none;
    color: #007bff;
    margin: 0 10px;
}

nav a:hover {
    text-decoration: underline;
}

footer {
    text-align: center;
    margin-top: 50px;
    padding-top: 15px;
    border-top: 1px solid #ddd;
    font-size: 0.9em;
    color: #666;
}

iframe {
    border: 0;
    display: block;
    margin-left: auto;
    margin-right: auto;
    max-width: 100%;
    width: 500px;
    aspect-ratio: 16 / 9;
}

main img {
    max-width: 100%;
    width: 500px;
    display: block;
    margin-left: auto;
    margin-right: auto;
    border-radius: 15px;
    border: 2px solid #000;
}

audio {
    display: block;
    margin-left: auto;
    margin-right: auto;
}

.audio-caption,
.image-caption,
.media-caption {
    text-align: center;
    font-size: 0.9em;
    font-style: italic;
    color: #555;
}