header {background:yellowgreen; padding: 0rem; margin: 0; padding: 0; height: 5rem; width: 100%}
main {display: flex;}
main section {background: lightblue; width: 70%; height: 65rem; margin: 0.5rem;}
main aside {background: grey; width: 30% ; height: 40rem ; margin: 0.5rem 0rem 0.5rem 0rem}
.primero {background: orange; height: 20rem ; margin: 2rem 0.5rem 0.5rem 0.5rem}
main section article {background: orange; height: 20rem; margin: 0.5rem}
footer {background: green ; height: 5rem; width: 100%}