CSS for “Related Post” advanced

I am building a blog post template that I will use for all my posts. I want to add a “Related Posts” summary block on the bottom using categories. I know how to add a summary block and select categories, but since I am building a template, I would like CSS that can pull up the categories from the current page automatically to display those related posts. 

Here is the template so far:

https://www.lucasano.com/blog-content/template-blog-post

Thanks!

Does anyone have a suggestion for this? Thank you!

Quote

I would like CSS that can pull up the categories from the current page automatically to display those related posts.

CSS is for styling how things look. It can't do things like lookup information and create new data structures. For that you would need JavaScript, the business plan or above, and custom JavaScript. Assuming it could be done at all. I know of no code that currently does this.