The advantage to creating these dividers is that you can apply specific classes to style them individually. Add dbl-indent to the class for your last .divider .
What is the difference between divider-s and hr-s? You can also style the hr elements, no? …
.divider in this case is a class, hr is an element
also the hr element has a semantic meaning
The <hr>HTML element represents a thematic break between paragraph-level elements: for example, a change of scene in a story, or a shift of topic within a section.
Historically, this has been presented as a horizontal rule or line. While it may still be displayed as a horizontal rule in visual browsers, this element is now defined in semantic terms, rather than presentational terms, so if you wish to draw a horizontal line, you should do so using appropriate CSS.
without more context I can’t answer - step 57 of which project? can you give the link?