Many Webflow designers have to create combo classes to remove the bottom margin from last-child elements. This is the most common use case and there are more. Supporting the last-child selector natively could speed up the building process and would be a great addition to Webflow in my opinion.
The link Christian posted works for Collection items only, whereas in my situation I'd like the last-child to apply to any last page Section inserted by someone who's not me (so they don't have to remember to add a class). Obviously there are ways to do this manually but they require everyone potentially touching the project to remember or know how as opposed to being configured to happen automatically.
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I think this is what you are looking for:
https://university.webflow.com/lesson/style-first-last-odd-even-items-in-your-cms
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