*{ margin: 0; padding: 0; box-sizing: border-box;}
*{ font-family: sans-serif }

header {width: 10%; color: white; background-color: #3daf4e; height: 5rem; }
header h1 {margin: 1rem; padding: 1rem; justify-content: space-around}

section {display: flex; flex-wrap: wrap; background-color: #ffffff; justify-content: space-around;}

article {width: 30%; background-color: #ffffff; height: 20rem; margin: 1rem;}


.articulo1 {width: 98%;}
.contenedor { max-width: 80rem; margin: auto}