I thought I’d just jump in here — I think you were asking a question basically about how the dotted line is added and the header is moved to the middle? It is included in the example’s internal CSS, so it is not obvious how this is done.
In situations like this, the browser’s developer tools are very useful. For example, in this case, hover your mouse pointer over one of the dotted lines, right-click on it (or Ctrl-click on macOS) and select the “Inspect” option, and the dev tools will appear. You can use them to see exactly what CSS is applied to the element.
In this case, it is quite a clever solution. First, generated content has been used to create pseudo-elements before and after the <h2> itself, and dotted borders have been added to these pseudo-elements:
If you hadnt pointed this out @chrisdavidmills I would not have picked it up. Also a great question @Sho_Sho123. I was just happy to use column-span on the .box class.
I have a followup question. How do you know what the space is between a rule and the paragraphs? Question 2 on multicol ask the reader to do the following “ensuring there is 10px of space between the edge of the rule and the column conten”. I cant figure out how to see this using the developer tools.
So, it is hard to find out exactly what the gap is between the columns when there is no specific value set. In the case of multi-col, the browser tends to take whatever information you give it (whether it is just a specific column width or count, column rule size, or whatever), and takes a “best fit” approach to make the columns work in the space available as best they can. This means that the columns and gutters may not work out exactly as big as you specify.