How to create an automatic outline side bar based on heading markdown of a post

I have successfully deployed my website using hugo theme JuiceBar via github. It cost me four days and I am so delighted!
My problem is: in JuiceBar developer’s demo page, there is a list of heading on the right side bar, which is built on the heading markdown order in the

However, even though I applied headings such as #, ##, and ### in my, my website doesn’t show the same sidebar as the developer’s demo site. And in my VS code I can still see my headings are correctly formatted as headings in the outline section on the left, such as:

Heading 1

Heading 2

How can I fix it and create an auto-sidebar? Thank you so much!

(BTW, I am also looking for ways to change the font size in my articles using JuiceBar.)

These are probably questions for the author of the theme.

thank you for your advise

Please look at the css as its not my problem just kicks the can down the road