.container {
  height: 100vh;
  background: gray;
}

nav {
  height: 10vh;
  background: red;
}

.wrapper {
  height: 90vh;
  background: blue;
}

.box {
  margin: 0 auto;
  height: 300px;
  width: 80%;
  background: yellow;
}

@media only screen and (min-width: 700px) {
  .box {
    display: none;
  }

  /* .multiple-boxes {
    display: block;
    height:
  } */
}