The following are articles that teach how to do something you may want to do and for me to refer to others who may want to know how too.
DOM, Grids and Reading Order for Accessibility – This is a running list of changes and warnings to help code a stable and accurate reading order for web pages.
Video – Understanding The PDF Tags Tree
Making PDF Files Accessible – “Properly structured, PDF documents can be made accessible to all site visitors, including those using a screen-reader or other assistive technologies.”
How to Use CSS for contrasting links colors within text for mouse over, focus states, etc.