The “Complementary Landmarks Check” evaluates whether all the complementary landmarks are not nested within other landmarks.
Example outcome
I noticed that the complementary landmarks are not contained within other landmarks.
Impact
Visual Impairments: Screen readers may not announce or provide access to complementary regions, especially if nested inside the main or article landmarks.
Motor Impairments: Navigating directly to complementary content (e.g., via keyboard shortcuts or ARIA landmark navigation) might become impossible if improperly nested.
Cognitive Disabilities: Inconsistencies in page layout can lead to misunderstanding the structure or purpose of side content.
Fixes
To address inappropriate complementary landmarks:
Locate the inappropriately placed complementary landmark.
Remove it from within the landmark in which it is nested.