body {
	margin: 0px;
}
.container {
  height: 100vh;
}

.header {
	background-color: gray;
  height: 10%;
}

.content {
  height: 70%;
  display: flex;
  justify-content: space-between;
}
 
.footer {
	background-color: purple;
  height: 20%;
}

.box {
	background-color: blue;
  height: 15%;
  width: 100%;

}

.main-body {
  background-color: red;
  height: 100%;
  width: 50%;
}

.box-container {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
	width: 50%;
}

.nav {
  list-style: none;
  display: flex;
  justify-content: space-around;
  padding: 0;
  margin: 0;
	height: 100%;
  align-items: center;
}

.nav li {
	font-size: 20px;
}

@media (max-width: 640px) {
  .content {
    flex-direction: column;
		justify-content: center;
    align-items: center;
  }
  
  .box-container {
  	width: 80%;
  }
  
  .box {
  	width: 100%;
  }
  
  .main-body {
  	width: 80%;
    height: 100%;
  }
}