.grid {
    display: grid;
    grid:
      "left .... right" 100px /
       1fr  10px   1fr;
}

.left-cell { grid-area: left; }

.right-cell { grid-area: right; }

.grid {
  display: -ms-grid;
  display: grid;
  -ms-grid-columns: 1fr 10px 1fr;
  -ms-grid-rows: 100px;
  grid:
      "left .... right" 100px /
       1fr  10px   1fr;
}

.left-cell {
  -ms-grid-row: 1;
  -ms-grid-column: 1;
  grid-area: left;
}

.right-cell {
  -ms-grid-row: 1;
  -ms-grid-column: 3;
  grid-area: right;
}