.container {
  display: grid;
  width: 900px;
  height: 900px;
  grid-template-columns: 1fr 3fr 1fr;
  grid-template-rows: 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr 1fr;
}
.header, .nav, .aside, .article, .footer{
    text-align: center;
    border: 1px black solid;
}
.header {
  
  background-color: linen;
  grid-row-start: 1;
  grid-row-end: 1;
  grid-column-start: 1;
  grid-column-end: 4;
  
}
.nav {

  background-color: lightcyan;
  grid-row-start: 2;
  grid-row-end: 10;
  grid-column-start: 1;
  
}
.footer {
  background-color: lightgray;
  grid-row-start: 10;
  grid-column-start: 1;
  grid-column-end: 4;
 
}
.aside {
  background-color: lightgreen;
  grid-row-start: 2;
  grid-row-end: 10;
  grid-column-start: 3;
 
}
.article {
  background-color: lightsteelblue;
  grid-row-start: 2;
  grid-row-end: 10;
  
}