label:has(#page-width-toggle) {
    display: inline-block;
    position: fixed;
    top: 2rem;
    right: 2rem;
    background-color: white;
    padding: 0.25rem;
    border-radius: 0.25rem;
    z-index: 1;
}
body:has(#page-width-toggle:checked) {
    max-width: min(50rem, calc(100% - 1rem));
    margin: 0 auto;
}