How is CSS pseudo content treated by screen readers?

Question

I've been told to be aware of CSS pseudo content because of the way it is treated by screen readers. Do you have any guidance?

Answer

CSS pseudo element content, either :before or :after, must only be used for decorative purposes. If you insert meaningful content using a :before or :after pseudo element, it is in violation of success criteria 1.3.1. This is a violation because certain assistive technologies may not be able to access the content inserted with css. So, those users would lose meaning from your web page.