All elements on post has the same margin bottom. To change it, locate the file "thegreatadventure/assets/css/main.css". Open this file with "Block Notes" an locate the line:

.post-template .post-content > * { margin-bottom: 3rem !important; }

3rem is equal to 3 lines. All elements on post (images, list, paragraphs ...) will have the same margin bottom.

The titles has other margin. If you want to change it, open file "thegreatadventure/assets/css/main.css" and locate the line:

.post-template .post-content h2, .post-template .post-content h3, .post-template .post-content h4, .post-template .post-content h5, .post-template .post-content h6{ margin-bottom: 2rem !important; }

This margin is only for the titles, and you can set as you want.

Proposed by Mathias