@media all and (max-aspect-ratio: 4/3) {
    body > main {
	margin: 10em 2em 1% 3%;
    }
}
@media all and (max-aspect-ratio: 4/3) {
    #utile {
	display: none;
    }
    code.bloc {
	display: inline-block;
	margin: 1em 0 0 0em;
	width: 90%;
    }
}
@media print {
    nav {
	display: none;
    }
    aside {
	display: none;
    }
    header {
	display: none;
    }
}