body{
background-color:black
background-size:cover;
}
header{
background-color:orange;
float:left;
width: 100% ;
height:100px;
}

main{
background:#f5f5dc;
  float:left;
width: 40% ;
}

nav{
  height:300px;
background:lime;
  float:left;
width: 30% ;
}

aside{
  height:300px;
background:#002137;
  float:left;
width: 30% ;
}

footer{
  height:100px;
background:pink;
color:white;
padding:15px;
border:1px solid black;
text-align:center;
}