Need a fix on the current table of content on blog posts pages

• When i scroll it should stay in the same page and highlight the section, see the refernce website i provided.
• Match the appearance of the table of content on the reference website.
• need the vertical line sepearating the content and table of content

reference image

reference site : https://codeharborhub.github.io/blog/google-summer-of-code-2026-complete-registration-guide-to-learn-code-earn-stipend/
Here is the refernece image code base.
https://github.com/codeharborhub/blog