body {
    font-family:Arial, Helvetica, sans-serif;
}

h1 {
    text-align: center;
}

iframe {
    border: solid 1px;
    width: clamp(50%, 800px, 75%);
    height: 500px;
    margin-bottom: 10vh;
}

pre {
    border: solid 1px;
    width: 50%;
}

@media (max-width: 800px) {
    iframe, pre {
        width: 100%;
    }
}

@Media (max-width: 600px) {
    pre {
        white-space: pre-line;
    }
}