body,
html,
h1{
  margin: 0;
  padding: 0;
}
body{
  background-color: aqua;
}
/* .app-container{
  background-color: teal;
  min-height: 100vh;
  width: 100vw;
}
@media (min-width: 400px){
  .app-container{
    max-width: 900px;
    width: 80vw;
    margin: 0 auto;
  }
} */
.filler{
  min-height: 50vh;
  width: 100%;
  box-sizing: border-box;
  border: 12px solid hsla( 0, 50%, 50%, 10%);
  background-color: teal;
}
.grid-container{
  display: grid;
  grid-template-rows: 30px auto 30px;
  grid-template-columns: 60% auto;
  grid-template-areas:
  ". . ."
  ". . aside"
  ". . .";
  align-items: stretch;
  place-items: stretch;
}
@media (max-width: 700px){
  .grid-container{
    grid-template-columns: 20% auto;
  }
}
@media (max-width: 400px){
  .grid-container{
    grid-template-columns: 0% auto;
  }
}
aside{
  grid-area: aside;
}