body {
  background-color: mediumturquoise;
  color: lightseagreen;
  font-family:verdana;}
  



  
  
.box {
max-width: 1000px;
margin: 50px auto;
display: grid;
grid-gap: 10px;
grid-template-columns: 250px auto;
}

header {
  grid-row: 1 / 2;
  grid-column: 1 / 3 ;
  border:darkseagreen  13px solid;
  background-color:#a9d2bd ;
  
  }
  
  
  nav {
  grid-row: 2 / 3;
  grid-column: 1 / 2 ; 
  height: max-content;
  border: darkseagreen 13px solid;
  background-color: #a9d2bd ;
  } 
  
  main {
  grid-row: 2 / 3;
  grid-column: 2 / 3;
   height: max-content;
  border:darkseagreen 13px solid;
  background-color:#a9d2bd;
  background-attachment: fixed;
  }
  
  footer {
  grid-row: 3 / 4;
  grid-column: 1 / 3;
  border: darkseagreen 13px solid;
  background-color:#a9d2bd ;
  }