Your Japanese Text Is Not Rendering Accessibly
Japanese web accessibility includes requirements that do not exist for Latin-script sites. CJK characters require larger base font sizes than Latin text to remain legible at the same point size. Line height needs to be set correctly for vertical density of Japanese text. Character spacing (letter-spacing) that works for Latin alphabets can break kanji readability. Vertical writing mode, when used, requires its own accessibility considerations. Sites built without attention to these specifics will fail users with low vision even if the underlying structure passes WCAG criteria.