body {
  font-family: Verdana, serif;
}

.container {
  display: flex;
  flex-direction: column;
}

header,
footer {
  background-color: rgb(98, 98, 98);
  color: white;
  font-weight: bold;
  flex-basis: 100%;
}

footer {
  font-size: .8em;
  order: 4;
}

header {
  order: 1;
}

aside {
  background-color: rgb(240, 240, 240);
  order: 3;
}

section,
header,
footer,
aside {
  padding: 1em;
  box-sizing: border-box;
}

section {
  background-color: rgb(180, 180, 180);
  order: 2;
}

@media screen and (min-width: 600px) {
  .container {
    flex-direction: row;
    flex-wrap: wrap;
  }
  aside {
    flex-basis: 33%;
    order: 2;
  }
  section {
    flex-basis: 67%;
    order: 3;
  }
}