Element to element reconversion

The editor should be loaded with items element that contains one item element in which user can edit content.

Adding new items (by pressing Enter key) or removing (by pressing backspace) should:

In threshold mode

Update items view element's data-amount attribute and change the list background color accordingly.

List of thresholds:

| Items    | Amount     | Color           |
|----------|------------|-----------------|
| 1 item   | single     | aquamarine      |
| 2 items  | little     | cadetblue       |
| 4 items  | few        | darkkhaki       |
| 7 items  | reasonable | darksalmon      |
| 10 items | high       | deeppink        |
| 15 items | huge       | mediumvioletred |

In HSL mode

Update items view element's inline style background color to hsl value with hue shifted by 5 every time an item is added or removed.

In none mode

Remove background color and update nothing.

Reconversion counter

In every mode you should be able to inspect number of times each item has been inserted.

This way you can observe increasing insertion counter on the main items element every time a child is either inserted or removed.

Main items element counter should also be increased when you change mode.