"What do MMA and writing CSS have in common?"

"The short version: categorise all uses of z-index as either local or global. Local: elements that need to render on top of a sibling or nearby element. Global: elements that must render on top of elements elsewhere on the page."

"Code can describe how, but it cannot explain why. This isn't a new concept, but it's a common theme I notice in helpful comments that I have come across. The ability to communicate something that the code cannot, or cannot concisely."

"Overview of the benefits of CSS variables and helpful tips and tricks for working with them."

"After writing (again) that it is ok to use tables, and after providing quick examples of responsive tables, I received questions about why I used some of the code I did. I am going to attempt to break it down to give you enough information to make your own responsive, accessible table because my example will likely not fit your case precisely (or closely?)."