What the standard says
When a user interface component receives keyboard focus, the component is not entirely hidden due to author-created content.
Why it matters
Focus lands somewhere the user cannot see, so the keyboard is working and the screen says nothing.
What a failure looks like
- failsA sticky top bar covering the field that just received focus after a Tab or an anchor jump.
How to fix it
- doAdd `scroll-margin-top` matching the header height, or shrink the sticky element on scroll.
How A11ySignal checks it
manual
No automated rule can judge this criterion, and we will not pretend otherwise. A clean scan does not mean 2.4.11 passes — it means nothing we can measure fails. This one needs a person.