html  {
  font-size: 62.5%;
  font-family: Arial, Helvetica, sans-serif;
}

body  {
  margin: 0;
}

page-container {
  display: grid;
  width: 100vw;
  height: 100vh;
  grid-template-rows: 10vh 1fr;
  grid-template-columns: 1fr 20vw;
}

header  {
  background-color: gray;
  grid-column: 1 / 4;
  grid-row: 1 / 2;
  display: grid;
}

main  {
  background-color: pink;
  grid-column: 1 / 2;
  grid-row: 2 / 3;
  display: grid;
}

footer  {
  background-color: yellow;
  grid-column: 2 / 3;
  grid-row: 2 / 3;
  display: flex;
  flex-direction: column;
}