body {
    background-color: #f4f8fb;
    color: #1f2933;
    font-family: Georgia, "Times New Roman", serif;
    margin: 10px;
}

header, nav, main, footer {
    max-width: 1000px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    color: #143d59;
    margin-bottom: 10px;
}

nav {
    text-align: center;
    background-color: #dbe9f4;
    padding: 12px;
    border: 1px solid #b7cad8;
    margin-bottom: 20px;
}

nav a {
    color: #0f3057;
    text-decoration: none;
    font-weight: bold;
    margin: 0 8px;
}

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

h2 {
    color: #143d59;
    margin-top: 25px;
}

p {
    line-height: 1.7;
    margin-bottom: 16px;
}

img, iframe, audio {
    display: block;
    margin: 15px auto;
    max-width: 100%;
}

figure {
    text-align: center;
    margin: 20px auto;
}

figcaption {
    font-style: italic;
    margin-top: 8px;
}

footer {
    text-align: center;
    border-top: 1px solid #b7cad8;
    padding-top: 12px;
    margin-top: 30px;
}

.validation-link {
    display: inline-block;
    margin-top: 8px;
}