WCAG conformance should be evaluated for color pairs specified in the content that an author would expect to appear adjacent in typical presentation. Authors need not consider unusual presentations, such as color changes made by the user agent, except where caused by authors' code.
例えば、用語のコントラスト比 注記6
https://waic.jp/translations/WCAG22/#h-note-96
https://www.w3.org/TR/2023/REC-WCAG22-20231005/#h-note-96
他の箇所にもあるかどうかを確認しておく