* { box-sizing: border-box< margin: 0; padding: 0 }
.contenedor {max-width: 75rem; margin: auto; }
header {width: 100%; background: #ffb2bf; height: 10rem; }
main {display: flex; justify-content: space-between; }
section {background: blue; width: 70%; height: 30rem; display: flex; flex-wrap: wrap; justify-content: space-around; }
article {width: 27%; background: orange; height: 40%; margin: 1rem 1rem 1rem 1rem; }
aside { background: #ddd; width: 30%; height: 30rem }
footer { width: 100%; background: green; height: 4rem; }