The intent of this Success Criterion (SC) is to ensure that people can override author-specified text spacing to improve their reading experience. Each of the requirements stipulated in the SC's four bullets helps ensure text styling can be adapted by the user to suit their needs.
The metrics set a target for a minimum increase in text spacing that must be met. Starting from the author's baseline implementation, any increase in spacing for any of these four style properties up to and including these targets should not result in the loss of content or functionality.
-This SC focuses on the ability to increase spacing between lines, words, letters, and paragraphs. Any combination of these may assist a user with effectively reading text. As well, ensuring users can override author settings for spacing also significantly increases the likelihood other style preferences can be set by the user. For example, a user may need to change to a wider font family than the author has set in order to effectively read text.