.mainbox{
  height: 650px;
  width: 850px;
  margin: auto;
  margin-top:5%;
  border: 3px solid pink;
}

.grid-container {
  display: grid;
  grid-template-areas: 
    'header header header header header ' 
    'left middle middle middle middle ' 
    'footer footer footer footer footer ';
    }
    
    
    .header {
  grid-area: header;
  background-color: #f1f1f1;
  padding: 30px;
  height: 15%;
  text-align: center;
  font-size: 35px;
  border-bottom: 3px solid pink;
}
    .left{
     grid-area: left;
     width: 20%;
     border-right: 3px solid pink;
    }
    .middle{
      grid-area: middle;
      width:80%;
     
    }
    
    .footer {
     grid-area: footer;
     border-top: 3px solid pink;
    }