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

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

header {width: 100%; height: 5rem; background: #123}
nav {width: 100%; height: 5rem; background: #555}

section {width: 100%; height: 15rem; background: #897; display: flex; justify-content: space-between; padding: 1%}
section article {width: 49%; background:#369; height: 10rem}

aside {width: 100%; height: 15rem; background: #456; display: flex; justify-content: space-between; padding: 1%}
aside article {width: 68%; background:#369; height: 10rem}
.treinta {width: 28%; background:#369; height: 10rem}

footer {width: 100%; height: 5rem; background: #dab152}