### Variant Markers
These classes don't apply styles themselves; their sole purpose is to mark an element so it can be targeted or referenced by a variant on another element.
Examples:
- `peer` is used by elements with the peer variant, to select a sibling
- `group` is used on parent elements of the group variants, to select an ancestor
https://v3.tailwindcss.com/docs/hover-focus-and-other-states#styling-based-on-parent-state
https://v3.tailwindcss.com/docs/hover-focus-and-other-states#styling-based-on-sibling-state