body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 20px;
}

header, nav, section, article, figure, aside, footer {
    background-color: white;
    padding: 15px;
    margin-bottom: 20px;
    border-radius: 8px;
}

nav a {
    margin-right: 15px;
    text-decoration: none;
    color: blue;
}

video {
    max-width: 100%;
}