Missing states
==============

Rule · bucket: judgment · severity: note · detector: none · since: v0.1.0
Section: Things to avoid
Group: States and interaction

Forbidden:
  A component with only a default appearance

Instead:
  Every interactive element defines: `hover`, `focus-visible`, `active`, `disabled`. Every data view defines: loading, empty, error, and partial/truncated.

A browser makes an `<iframe>` a tab stop whether or not anything in it can be used. One that only shows something, with nothing inside to operate or scroll, is taken out of the tab order (`tabindex="-1"`) rather than given states it has no use for; a keyboard reader otherwise meets a stop with nothing to see. One the reader uses (a player, a map, a form) keeps its stop and shows focus.