.container {
  border: 1px solid red;
  height: 100vh;
  display: grid;
  grid-gap: 10px;
  grid-template-rows: 70vh;
  grid-template-columns: 30% auto;
}

* {
  margin: 0;
  padding: 0;
}

.sidebar, .main, .nav {
  background-color: gray;
}

.nav {
  grid-column-start: 1;
  grid-column-end: 3;
}