grid-template-areas in css code example

Example 1: how to use a blank space with grid template areas css

.container {
  display: grid;

  grid-template-columns: 2fr 2fr 1fr 2fr;
  grid-template-rows: 100px 200px 100px;

  grid-template-areas:
    "head head . side"
    "main main . side"
    "footer footer footer footer";
}

Example 2: unknown property grid-template-areas

.sidebar{
    	grid-area:sidebar;
      background:aqua;

    }
    .grid_container{
    	display:grid;
    	grid-template-columns: 1fr 3fr;
      grid-template-rows: 1fr 3fr;
    	grid-template-areas:
    	"sidebar ."
    	"sidebar .";
      background:pink;
      height:300px;
    }