*{box-sizing: border-box; margin: 0;padding: 0;}

header{background-color: blue; height: 200px; max-width:1280px; margin: auto; text-align: center; color: #FFFFFF}
.contenedor{max-width: 1280px; margin: auto; background-color: aqua; display: flex; border: #000 0.1rem solid}
.seccion{display: flex; justify-content: space-between;}
section{margin:auto; max-width: 100%; margin: 1rem 0 0.5rem 0}
.seccion article{text-align: center;background-color: blueviolet; margin: 0.5rem 1rem 0.5rem 1rem;height: 300px; width: 60%}

main section{width: 100%}
main aside{width: 30%; text-align: center; background-color: aquamarine}

footer{background-color:crimson ; height:100px; max-width:1280px; margin: auto; text-align: center;color: #FFFFFF}
main section p{text-align: center}