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

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

header{ height: 10rem; background: #08b908; opacity: 0.5; }

nav{height: 2rem; background: #ed37b5; opacity: 0.5; }

section{height: 40 rem; background: #64cceb; }

section{display: flex;
	flex-wrap: wrap;
	justify-content: space-between; }

article{background: #fd9720; }
.primero{width: 48%; height: 22rem; border-style: solid; border-color: #64cceb }
.segundo{width: 48%; height: 22rem; border-style: solid; border-color: #64cceb}

aside{height: 18rem; background: #bfbfbf;
	display: flex;
	flex-wrap: wrap;
	justify-content: space-between; }
.tercero{width: 70%; height: 18rem; border-style: solid; border-color: #bfbfbf }
.cuarto{width: 26%; height: 18rem; border-style: solid; border-color: #bfbfbf }

footer{height: 5rem; background: #3b7942; opacity: 0.5%; }