Collapsing headings: How do you tell it to 'stop here' or 'Don't collapse empty lines after text but before the next heading'

I found a comment on reddit that suggested adding a blank space before each header to make it so that only text with indents under it count as part of that headers section.

This almost works.

It works but it also breaks checkboxes which require the first checkbox to be unindented. Does anyone know a CSS solution that adds an exception to allow checkboxes to have their first one be indented?