.container {
  display: grid;
  grid-template-columns: 200px 1fr;
  grid-template-rows: auto auto auto;
  gap: 10px; 
}

header {
  grid-column: 1 / 3;
  background: #ddd;
  padding: 20px;
}

nav {
  grid-column: 1 / 2;
  grid-row: 2;
  background: #cce;
  padding: 20px;
}

main {
  grid-column: 2 / 3;
  grid-row: 2;
  background: #cec;
  padding: 20px;
}

aside {
  grid-column: 1 / 2;
  grid-row: 3;
  background: #ecc;
  padding: 20px;
}

footer {
  grid-column: 1 / 3;
  grid-row: 4;
  background: #ddd;
  padding: 20px;
}

.extra {
  grid-column: 2 / 3; 
  grid-row: 3;        
  background: #eef;
  padding: 20px;
}