Header

      /* You start with this code: */

      .grid {
        display: grid;
        grid-gap: 10px;
        grid-template-columns: repeat(60, 1fr)
      }


      /* And this is your code: */

      #header, #footer { grid-column: 1 / 61 }

      #sidebar { grid-column: 1 / 17 }

      #article { grid-column: 17 / 61 }