Layers define the depth, or z-index, of an element. | Variable | Default value | | ---------------------- | ------------- | | `--layer-cover` | `5` | | `--layer-sidedock` | `10` | | `--layer-status-bar` | `15` | | `--layer-popover` | `30` | | `--layer-slides` | `45` | | `--layer-modal` | `50` | | `--layer-notice` | `60` | | `--layer-menu` | `65` | | `--layer-tooltip` | `70` | | `--layer-dragged-item` | `80` |