.box{
   max-width: 1000px;
   margin: 90px auto;
   display: grid;
   
   
}

 header{
   border: 2px transparent solid;
   grid-row: 1/2;
   grid-column:1/3;
   height: 90px;
}

 main{
   grid-row: 2/3;
   grid-column: 1/3;
   border: 2px transparent solid;
   height: max-content;
}
 
 nav{
   grid-row: 3/4;
   grid-column: 3/4;
   border: 3px transparent solid;
   width: 300px;
   height: max-content;
}
 
 footer{
   grid-row: 4/5;
   grid-column: 1/3;
   border: 3px transparent solid;
}