body{
	height: 100vh;
	width: 100vw;
	display: flex;
	flex-direction: column;
}


header{
	height: 10%;
	background: powderblue;
}

footer{
	height: 10%;
	background: aquamarine;
}

body > div{
	flex-grow: 1;
}

.flex-row{
	display: flex;
	flex-direction: row;
	width:900px;
	margin:0 auto;
	margin-top:40px;
}

main{
	background: gainsboro;
	height:100%;
	flex-grow: 1;
	width:80%;
}

aside{
	width: 20%;
	background: lightsalmon;
}

@media screen and (max-width: 600px) {
	aside{
		width: 100%;
	}
	main{
		width:100%;
	}
}