@media (min-width: 768px) {
  .container {
    display: grid;
    grid-template-columns: 200px 1fr 200px;
    grid-template-rows: auto 1fr auto;

  }
}

header {
  grid-column: span 3;
  padding: 30px;
  text-align: center;
  font-size: 1.4em;
  background-color: #369;
  color: white;
}

main {
  flex: 1;
  padding: 20px;
}

nav {
  background-color: #f90;
  padding: 20px;
  grid-template-columns: 2fr;
  grid-template-rows: auto 1ft auto;
}
 
aside {
  padding: 20px;
  background-color: #936;
}

footer {
  grid-column: span 3;
  padding: 30px;
  text-align: center;
  font-size: 1.4em;
  background-color: #690;
  color: white;
}

h1 {
  margin-bottom: 1em;
  font-size: 1.3em;
  font-weight: bold;
}