Customizing Drupal content placement can be tricky. If you have a piece of content
that appears in more than one area, you may need flexibility in your CSS to style the elements independently of one another.
What has worked well for me is CSS selectors that utilize the cascading nature of CSS for advanced
In the SS, you can see that the selector combined a class and an ID. The ID is for the individual node, in this case an amazon book ad generated externally, and the class is for the page itself. It’s important to note that the selector will work as long as the two selectors are in the same hierarchy. I could just use the ID but that is assigned to the individual node and that node appears (may or may not, hard to tell with Drupal) in other areas. Style by the ID, fix one, break the other. But, using the class of the page and the ID of the node allows an easy to find hierarchy that will cascade every time for that page and will only hit that element on that page. So unless you have the same node twice on the same page, this will always allow consistent styling selection.