direction: right
outer-grid -> outer-container

outer-grid: {
  grid-columns: 1

  inner-grid -> container -> etc

  container: {
    label.near: top-left
    # edges not yet supported here since they must be direct grid children
    a
    b
    c
  }

  inner-grid: {
    grid-rows: 1
    1
    2
    3
    # edges here are not supported yet since this is inside another grid
  }
}

outer-container: {
  grid -> container

  grid: {
    grid-rows: 1
    # direct child edges ok in least nested grid
    1 -> 2 -> 3
  }

  container: {
    # non grid edges ok
    4 -> 5 -> 6
    nested container: {
      # nested non grid edges ok
      7 -> 8
    }
  }
}