That has to do with mobile responsiveness, which we will cover in much more detail later in this course. If you’re curious and want to look into it earlier, take a look at this post, which was the assignment for it when I last taught this course:
Aside from font-size being first, order does not matter.
You can add more properties if you want as long as you include all the things the example code had with different values.
Span sandwiches (as I call them) will be covered later.
margin: auto; works in some cases. There are more ways but we’ll be covering those later when we talk about multicolumn threads.
