header { background: green; height: 8rem;}
nav { background: pink; height: 2rem;}
section { background: #9cd5ff; height: 30rem;display: flex; flex: wrap;justify-content: space-around;}
article { background: orange; height: 26rem;  width: 49%; margin-top: 3rem;}
aside { background: grey; height: 25rem;display: flex; flex: wrap;justify-content: space-around;}
.grande { width: 69%; height: 20rem; }
.chico { width: 29%; height: 20rem; }
footer { background: green; height: 6rem;}