body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background-color: #f4f8fb;
}

header {
    background-color: #4a90e2;
    color: white;
    text-align: center;
    padding: 30px 20px;
}

nav {
    background-color: #2d3e50;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 12px;
    display: flex;
    justify-content: center;
    gap: 20px;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: bold;
    padding: 6px 10px;
    border-radius: 4px;
    transition: background 0.3s;
}

nav a:hover {
    background-color: #4a90e2;
}

main {
    padding: 20px;
}

.contenido {
    background: white;
    margin: 25px auto;
    padding: 20px;
    max-width: 900px;
    border-radius: 10px;
    box-shadow: 0px 0px 10px rgba(0,0,0,0.1);
}

.contenido img {
    width: 100%;
    margin-top: 10px;
    border-radius: 10px;
}