grid area top top

1.item-a {
2  grid-area: header;
3}
4.item-b {
5  grid-area: main;
6}
7.item-c {
8  grid-area: sidebar;
9}
10.item-d {
11  grid-area: footer;
12}
13
14.container {
15  display: grid;
16  grid-template-columns: 50px 50px 50px 50px;
17  grid-template-rows: auto;
18  grid-template-areas: 
19    "header header header header"
20    "main main . sidebar"
21    "footer footer footer footer";
22}