Customized TOC for blog

Anybody know how to make table of contents looks like this? 

I only find a solution to make like this.https://mishkinart.com/blog/squarespace-table-of-contents/#css

So i think maybe i can make it better.

If your posts are in a blog you can create an archive block and group by post, category in a list view, and place the block on any page. If you want to create a table of contents for pages, then create a text block and place links to each content in the block.