body {
    margin: 10px;
    margin-top: 1em;
    margin-bottom: auto;
    background-color: antiquewhite;
    color: black;
    font-family: 'Times New Roman';
}

h1 {
    text-align: center;
    font-size: 2.5em;
}

h2 {
    text-align: center;
    font-size: 1.5em;
}

h3 {
    text-align: center;
    font-size: 1.5em;
}

h4 {
    text-align: center;
    font-size: 1.5em;
}

nav {
    text-align: center;
}

figure {
    text-align: center;
}

p, div {
    margin: 10px;
    padding: 10px;
    line-height: 1.5em;
}

.centered-image {
    display: block;
    margin-right: auto;
    margin-left: auto;
    max-width: 100%;
    height: auto;
    border: 1px solid #000000;
    border-radius: 10px;
}

div, iframe {
    display: block;
    margin: auto;
}

div, audio {
    display: block;
    margin: auto;
}

footer {
    text-align: center;
}

#validation {
    text-align: center;
}

@media only all and (max-width: 550px) {
    img {
        display: none;
    }
}