CSS how to add padding between list items?

Question

css

Good evening, there is a list of elements

• First element
  
• Second element
  
• Third element
  

And when you click on the first element with the li tag, the nested text appears:
First element
Here is the text associated with the first element
Second
element

Answer 1

https://codepen.io/anon/pen/rJJNzM
Implement like this.