css grid area names

1.grid {
2  display: grid;
3  grid-gap: 20px;
4  grid-template-rows: [header-start] 20vh [header-end] ;
5  grid-template-columns: [sidebar-start] 1fr 2fr [sidebar-end] 1fr 2fr 1fr 2fr;
6}
7
8.header {
9  grid-row: header-start;
10  grid-column: 1 / -1;
11}
12
13.sidebar {
14  grid-row: 2;
15  grid-column: sidebar-start / sidebar-end;
16}
17